Method and circuit for using polarized device in AC applications

ABSTRACT

Polarized electric charge storage devices economically provide high available capacitance. The present invention directly employs polarized electrical charge storage (PECS) devices such as polarized capacitors or electrochemical batteries in general AC applications with a novel circuit topology. In one embodiment, an anti-series configuration of first and second PECS devices are used within an AC network for enhancing operation of the AC network. At least one DC source is provided for maintaining the PECS devices forwardly biased while they are subjected to an AC signal. The AC signal, which drives an AC load, is applied to the anti-series devices. The devices are sufficiently biased by the at least one DC voltage source so that they remain forwardly biased while coupling the AC signal.

This specification claims the benefit of provisional application SerialNo.: 60/174,433, entitled “Method and Circuit for Using Polarized Devicein AC Applications,” filed: Jan. 4, 2000.

TECHNICAL FIELD OF THE INVENTION

The present invention generally relates to the use of polarizedelectrical charge storage devices in AC applications. In particular, thepresent invention relates to biasing polarized devices, such aspolarized capacitors with a DC potential for uses in general ACapplications.

BACKGROUND

Capacitors are used for a variety of purposes including energy storage,signal coupling, motor starting, power factor correction, voltageregulation, tuning, resonance and filtration. In series and shuntimplementations, there are many operational advantages, both transientand steady state, for implementing capacitors in general AC networks.

Network efficiency is increased with power factor improvement, duringtransient conditions. Transient applications of series capacitorsinclude voltage surge protection, motor starting, current limiting,switching operations and the like. Series capacitors can moderate theeffects of AC network faults and other transient conditions. Forexample, low power factor transient currents are associated withmagnetic inrush currents due to motor starting, transformer inrush andfault currents. Series capacitance improves the overall power factor andnetwork voltage regulation during these transient conditions. Seriescapacitor banks also demonstrate a degree of current limiting due to theseries impedance of the capacitor. This reduces fault currents and thusreduces generator, transformer, switchgear, bus and transmission linesize requirements. The capacitor in series with the fault acts as acurrent limiting device. Tuned circuits composed of inductors andcapacitors (LC circuits) are used for filtration. A high inductionseries version can dramatically increase network fault impedance bydeliberately shorting out the capacitor bank. A series capacitor bank istypically coupled to a transformer. Transformer opposition toinstantaneous current change combines with capacitor opposition toinstantaneous voltage change. These characteristics lead to greaterinstantaneous network voltage stability as a result of increased use ofseries capacitor banks. Secondary effects include voltage surgeprotection, demand factor improvement and voltage regulation.Instantaneous power transfer efficiency can be improved with propercapacitor use. While these many series capacitor advantages are wellknown, and proven in the lab, unit cost and size requirements haveprevented their general implementation.

AC network steady state characteristics are also improved through theincorporation of capacitors. High capacitance, series applicationsimpress a low steady state AC voltage on the capacitor. This is helpfulwhen electrical transfer devices are used in conjunction with seriescapacitor banks. Electrical wave distortion is similarly reduced withincreasing capacitance. Steady state series capacitor applicationsinclude motor running, filtration, power factor correction, efficientpower transfer, voltage boosting and the like. Series capacitor banksallow induction generators to power induction motors, by providing therequired magnetizing [VARs] for both devices. This can also improve thepower quality, while reducing the cost of electric grid alternativesources, emergency power supplies, mobile equipment and portablegenerators. Mechanical stress associated with bringing additionalgeneration capacity, on line, to synchronous operation, can be moderatedby the presence, of series capacitive coupling.

The two major capacitor categories are polar and non-polar. There aremany realizations of each category. Due to their uni-directional,forward biasing requirements, polarized capacitors are mostly used in DCand small AC signal applications. Polarized capacitors are widely usedin DC filtering applications, such as output stages of DC powersupplies. Audible frequency (music) amplifiers use a DC biased polarizedcapacitor to couple signals. Conversely, non-polarized capacitors aregenerally useful in both DC and general AC applications. Unfortunately,non-polarized capacitors—especially in series applications—are not wellsuited for many AC and DC uses due to their limitations in size,capacitance, weight, efficiency, energy density and cost. The use ofundersized non-polar capacitor banks causes significant current waveformdistortion and a large voltage drop across the capacitor, which resultsin energy losses and poor AC voltage regulation at the AC load.

Conversely, polarized capacitors, as well as other polarized electriccharge storage (PECS) devices, have a low cost per unit of capacitance,as well as smaller mass and dimensions, as compared with nonpolarcapacitors. These characteristics favor their use over non-polarizedcapacitors. They also exhibit a relatively low series AC resistance atpower frequencies. However, they may only be effectively operated withpositive “forward” voltages relative to their positive and negativepoles. A reversed voltage of any significant magnitude causes thecapacitor to short, which usually results in an explosion that can becomparable to that of a hand grenade. In fact, with solid tantalumcapacitors, this short circuit failure mode includes spontaneouscombustion. Thus, polarized capacitors, for the most part, have not beenamenable for general AC applications.

FIG. 1 models the normal operation of a polarized aluminum electrolyticcapacitor as well as circuit operation in over-voltage and reverse biasvoltage mode. The model consists of series inductor 101, series resistor102, parallel resistor 103, zener diode 104 and polarized capacitor 105.Zener diode 104 models the forward and reverse shorting conditionpresent when the impressed voltage exceeds a reverse bias voltage of 1.5Volts or a forward bias condition of approximately 50 Volts over therated working DC voltage (WVDC) of the capacitor. Inductor 101 issuitable for modeling the self-resonant frequency of the capacitor. Theseries resistor 102 models the (small, mΩ) equivalent series resistance(ESR) measured in capacitor operation. The parallel resistor 103 modelsthe (large, MΩ) equivalent parallel resistance measured in capacitor DCleakage current phenomenon. In low frequency operation, forward biasedvoltage within the device working voltage conditions will allow signalcurrent flow through the directional capacitor 105. Reverse biasconditions will occasion a short through diode 104.

The capacitor will suitably operate continuously between zero volts andthe rated working DC voltage. A reverse bias voltage of up to about 1.5volts DC to a rated forward bias surge voltage defines the outer limitsof appropriate transient use of the capacitor. Capacitor operationoutside this wider voltage envelope will cause short circuit conditions.There is typically a third, higher impulse voltage parameter. Excessiveforward voltage on the capacitor will cause a reverse current flowthrough zener diode 104. This electrical behavior is schematicallymodeled by depicting a zener diode 104 in parallel, but with oppositepolarity alignment than the polar capacitor. Shorting through diode 104,in either direction permits excessive current, heat buildup, whicheventuates capacitor failure. This is why a single polarized capacitorfails in normal AC operation.

FIG. 2 depicts a simple circuit realization 250 that illustrates atypical prior art use of a DC biased polarized capacitor in a small ACsignal coupling application. This circuitry is commonly used as alaboratory exercise for undergraduate analog electronic students and isemployed in multi-stage amplifiers. Circuit 250 includes an AC signalsource 255 superimposed upon a DC bias voltage source 260, a capabilityof lab power supplies. The AC signal is coupled to the load 266, whilethe DC bias voltage is blocked by and positively biases a polarizedcapacitor 262. The capacitor and DC bias voltage are selected so thatthe superimposed AC and DC voltages are at all times within the propervoltage window. The AC source output section conducts the entire DCpower source output, and vices versa. As the AC signal increases inmagnitude relative to the capacitor rated DC working voltage, waveformdistortion in the form of clipping occurs. Thus, the lowest waveformdistortion occurs for small AC signals. The magnitude of the biasvoltage is typically on the order of half the rated capacitor DC workingvoltage. The fidelity of AC waveform transfer improves as the magnitudesof the AC voltage signal, and the AC current are decreased.

A non-polarized capacitor 264 is shown in parallel with the polarizedcapacitor 262 for “polishing.” Non-polarized polishing capacitors may beused for fine-tuning resonance, adjusting capacitance to current ratio,reducing ESR, adjusting bandwidth, improving waveform transfer,flattening the frequency response and improving other such applicationspecific aspects. The capacitance of the polarized capacitor 262typically may exceed that of the polishing capacitor 264 byapproximately two orders of magnitude. The non-polarized polishingcapacitor works to reduce distortion of the signal.

FIG. 3 shows Circuit 300, which includes AC source 305, anti-seriespolarized capacitors 312, 314, collectively referred to as 310 and ACload 320. The polarity marks, above the caps, show an instantaneousforward bias condition of capacitor 312 and a simultaneous reverse biascondition of capacitor 314, which occurs during a positive phase of ACsource 305. (Of course, the polarities would be reversed during thenegative phase.)

Anti-series configurations of polarized capacitors will operatetransiently, or in current limited applications. Such a conventionallyimplemented, anti-series configuration exploits the previously describedinternal zener diode-like behavior. It is typically used in single-phasemotor starting applications and is plagued by overheating and short lifedue to reverse bias shorting. When capacitor 312 is forward biased bythe AC source, capacitor 314 is reverse biased and shorts the half wavecurrent to the load 320. On the next half wave, capacitor 314 is forwardbiased while capacitor 312 is shorted. This conventional anti-seriesconfiguration is notable for a DC bias condition, which oscillates on asub-cycle (half cycle) basis.

With reference to FIG. 4, U.S. Pat. Nos. 4,672,289 and 4,672,290 toGhosh teach an improved scheme for implementing anti-series, polarizedcapacitors in AC, environments. Circuit 460 is shown in FIG. 4. Circuit460 includes polarized capacitors 462, 464 and diodes 466, 468 in serieswith AC source 461 for driving AC load 470. Anti-series symmetricalpolarized capacitors 462, 464 are in parallel with oppositely alignedanti-series diodes 466, 468. In operation, a parallel “shunt” diode(466, 468), clamps the maximum instantaneous negative voltage acrosseach capacitor, which protects each polarized capacitor from beingexcessively reverse biased. The Ghosh circuit provides external discretediodes to shunt the reverse currents away from each capacitor. Theinternal zener diode-like behavior is reduced. This reduces the heatbuild-up in the capacitors and extends their expected life.

Unfortunately, however, this shunting diode solution has certainmaterial drawbacks. Each capacitor polarity is subjected to the full ACvoltage, across the assembly, for one half of the AC waveform. Thus fora short circuit, motor starting, transformer inrush or similarcondition, the entire AC source tension is impressed across theterminals, of each anti-series capacitor, and diode assembly, with a 50%duty cycle. No volt divider is present. Thus, the realizable AC ripplevoltage is limited to available diode voltage ratings, for a given levelof AC signal distortion. In addition, each polarized capacitor issubjected to a low voltage, reverse bias condition approximately 50% ofthe time. The diodes distort the AC network voltage waveform. Moreover,the self-biasing circuitry is not amenable to diode current limitation.These are problems in the steady state condition, due to heat loss,current waveform distortion and diode size requirements. These are evenmore significant problems for semiconductors in transient, fault,magnetizing inrush, resonance and/or starting applications. The entirecircuit current passes through each diode with a 50% duty cycle in boththe steady state and the transient case. This results in a significantheat loss through the diodes. Also, the self-bias DC voltage oscillationperturbs the system ground reference and further adds to the heatdissipation. AC signal distortion is present due to clipping as a resultof inadequate DC bias voltage relative to the AC signal size. The energyrequired for capacitor charge reformation per half cycle is a furtherenergy loss. In addition, this prior art solution is not suitable foruse with other polarized charge storage devices such as manyelectrochemical batteries.

Furthermore, the circuit exhibits an absence of economy of scale forincreased current requirements. If the capacitor bank amperage rating isdoubled, so too must the diodes, heat sinks and the like. Thisconstitutes a major capital expense in high current AC applications. Ifadditional series diodes are required to increase the realizable voltagelevel, the additional diodes must have the same ampacity as the existingdiodes. The forward voltage drop of, each existing diode, is matched, bythe forward voltage drop of, each additional unit. Thus, power loss andheat generation increase proportionally. Also, the dead-zone about zero,of each diode, is multiplied, by the number of diodes in series.

This waveform distortion, due to the anti-series diode placement, e.g.,in the Ghosh circuit, and the internal zener diode behavior in theconventional anti-series arrangement is thus intractable. In addition,the Ghosh and conventional circuits have an ongoing oscillatory effecton the system DC ground reference. These problems make the conventionaland Ghosh devices unsuitable for general AC applications. These twotechnologies operate outside of the small signal regime wherein ACvoltage distortion can be minimized.

With reference to FIG. 5, German Patent No. DE4401955 to Norbertdiscloses a circuit 500 for using polarized capacitors in transient ACapplications. As taught by Norbert, circuit 500 is designed to beprimarily a phase shifter for starting single-phase asynchronous motors.The circuit 500 is composed of AC source 501, anti-series pair 502,resistor 503, diode 504, inductive load 505 and switch 506. Diode 504and resistor 503 are permanently connected to the AC voltage source 501or alternately to a different negative voltage source. After a latencyperiod with switch 506 open, the diode/resistor combination willgradually forwardly bias the capacitor pair. The Norbert circuitpreconditions the capacitor for proper starting of the AC load, andincreases the expected life over that of the Ghosh circuit when anadequate latency period is available prior to motor starting. Norbertallows the use of small diode ampacities relative to Ghosh. Norbert alsoproposes a high impedance connection to the anti-series capacitor centernode, in an economic single can configuration. Only external diode,resistor and AC source connections are required to render the circuitready for use.

Unfortunately, The Norbert circuit requires substantial time forcapacitor biasing. The capacitors are charged to just under themagnitude of the AC voltage (peak to zero). For this reason, the Norbertcircuit is incompatible with the use of low working voltage polarizedcapacitors in high AC system voltage applications. In addition, thecircuit is unsuitable for use with other polarized charge carrierdevices such as electrochemical batteries. Moreover, the Norbert circuitis unsuitable for continuous use in that the reforming charge tends todeteriorate over time if the single-phase motor or other load remainsconnected following start. The circuit will then behave identically tothe conventional, uncharged anti-series configuration. The Norbertcircuit will thus exhibit the disadvantage of clipping the AC waveformsignal due to exceeding the small AC signal requirement in the steadystate case.

Accordingly, a need remains for an improved method and circuit for usingpolarized charge storage devices such as polarized capacitors in ACapplications including steady-state AC applications.

SUMMARY OF THE INVENTION

Polarized electric charge storage devices economically provide highavailable capacitance. The present invention directly employs polarizedelectrical charge storage (PECS) devices such as polarized capacitors orelectrochemical batteries in general AC applications with a novelcircuit topology. In one embodiment, an anti-series configuration offirst and second PECS devices are used within an AC network forenhancing operation of the AC network. At least one DC source isprovided for maintaining the PECS devices forwardly biased while theyare subjected to an AC signal. The AC signal, which drives an AC load,is applied to the anti-series devices. The devices are sufficientlybiased by the at least one DC voltage source so that they remainforwardly biased while coupling the AC signal.

The foregoing has outlined rather broadly the features and technicaladvantages of the present invention in order that the detaileddescription of the invention that follows may be better understood.Additional features and advantages of the invention will be describedhereinafter, which form the subject of the claims of the invention. Itshould be appreciated by those skilled in the art that the conceptionand specific embodiment disclosed may be readily utilized as a basis formodifying or designing other structures for carrying out the samepurposes of the present invention. It should also be realized by thoseskilled in the art that such equivalent constructions do not depart fromthe spirit and scope of the invention as set forth in the appendedclaims.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present invention and theadvantages thereof, reference is now made to the following descriptionstaken in conjunction with the accompanying drawings, in which:

FIG. 1 is a prior art circuit model for electrolytic capacitors.

FIG. 2 depicts a prior art circuit employing polarized and unpolarizedcapacitors in a small AC signal coupling application typically presentin analog audio amplifiers.

FIG. 3 shows a commercially available conventional antiseries polarizedcapacitor pair coupling an AC signal to an AC load typically used inmotor starting applications.

FIG. 4 shows a prior art improvement to the circuit of FIG. 3.

FIG. 5 also depicts a prior art improvement to the circuit of FIG. 3.

FIG. 6A shows an AC circuit comprised of forwardly biased, anti-seriespolarized capacitors, of the present invention, neglecting the DC biascircuitry details.

FIG. 6B depicts a forwardly biased, anti-series polarized capacitorconfiguration, of the present invention, with an AC device separatingthe positive DC junction node, with biasing details omitted.

FIG. 7 illustrates an anti-series symmetrical implementation of DCbiased polarized capacitors in a limited AC application of the presentinvention.

FIG. 8 depicts one circuit of the present invention.

FIG. 9 depicts another circuit embodiment of the present invention.

FIG. 10 shows one embodiment of a circuit for implementing the presentinvention.

FIG. 11 illustrates a capacitive power coupling arrangement utilizinganother embodiment of the present invention.

FIG. 12 shows a three-phase, three-wire AC system series depictionincorporating forwardly biased, anti-series polarized capacitors, of thepresent invention, neglecting the DC bias circuitry details.

FIG. 13 shows a three-phase, four-wire AC system incorporating anembodiment of the present invention.

FIG. 14 shows an alternate three-phase, four-wire AC systemincorporating another embodiment of the present invention.

FIG. 15 illustrates an additional three-phase, four-wire AC systemincorporating an embodiment of the present invention.

FIG. 16 illustrates one high current circuit with a 4n+ implementationof the present invention, omitting the details of the DC voltage source.

FIG. 17 shows a simple representation of a high voltage realization of a4n+ polarized capacitor and biasing system of the present invention.

FIG. 18 illustrates an alternate, realization of the present invention.

FIG. 19 depicts the two winds of a split phase AC induction motorsuitable for continuous operation from a single phase AC source,employing an embodiment of the instant invention.

FIG. 20 shows a band pass LC filter with a detuning device for limitingcurrents caused by downstream faults in another embodiment of thepresent invention.

FIG. 21 depicts an electrically touch safe, thermally conductivestructure for adjusting capacitor temperatures and electrical parametersin another embodiment of the present invention.

FIG. 22 illustrates a method for establishing a forward biased smallsignal transfer condition suitable for transient applications, andadaptable to continuous operation in another embodiment of the presentinvention.

FIG. 23 depicts a simple controlled biasing circuit, in anotherembodiment of the present invention, suitable for continuous operation.

FIG. 23A is a simplified schematic of the charging mechanism of FIG. 23.

FIG. 24 depicts another embodiment of the present invention with apassive biasing circuit similar to FIG. 23.

FIG. 25 depicts an antiseries configuration of the present inventionwherein the AC source separates the negative capacitor terminals and theAC load separates the positive capacitor terminals.

FIG. 26 illustrates the use of a single low voltage DC voltage source tobias two antiseries polarized capacitor pair, which are in series witheach other:, in another embodiment of the present invention.

FIG. 27 illustrates a DC power supply, in another embodiment of thepresent invention, wherein a rectifier bridge is coupled to the ACsupply via antiseries capacitors, which are in turn biased by a portionof the DC output.

FIG. 28 shows a three phase antiseries PECS device configuration, inanother embodiment of the present invention, wherein a single polarizedcapacitor is present in each AC hot leg.

FIG. 29 shows a 120:240 Volt single-phase system of the presentinvention, wherein a single PECS device in each leg serves as part of ananti-series capacitor configuration.

FIG. 30 shows a DC bias source using a single rectifier in an antiseriesPECS device configuration of the present invention suitable forcontinuous operation.

DETAILED DESCRIPTION Overview

FIG. 6A shows ideal circuit 600, which conceptually illustrates anembodiment of the present invention. Circuit 600 includes AC source 605connected in series with an anti-series, polarized capacitor pair 610and load 620, which is driven by AC source 605. Polarized, anti-seriescapacitor pair 610 includes polarized capacitors 612 and 614 connectedin an anti-series relation to one another. As shown in FIG. 6A,capacitors 612 and 614, are each suitably and forwardly biased with DCvoltages 616, 618 so that a net positive potential is continuouslyimpressed across each capacitor thereby allowing them to be used ingeneral AC applications.

Each DC biasing voltage is large enough in connection with eachcapacitor's operational AC voltage share to compensate for the worsecase negative AC swing. The positive swing of the AC voltagesuperimposed on the DC bias voltage is similarly less than thecapacitor's rated working voltage. The forced, continuous DC biascondition eliminates the prior art disadvantages of intractable heatloss, short life, signal distortion and/or an oscillatory DC biasvoltage condition. Thus, when the proper DC bias condition is maintainedand the AC voltage and current are small relative to device tolerances,this circuit is suitable for steady state and/or transient AC operation.The details of the DC bias superposition circuitry are omitted forsimplicity in this drawing but will be addressed in greater detailbelow. There are many circuit realizations suitable for establishing andmaintaining the proper DC capacitor bias condition. The DC sources forbiasing anti-series, polarized capacitors may be derived from anysuitable scheme including both regulated and unregulated sources.Alternatively, note that instantaneous active biasing is practical andcan increase life of polarized capacitors.

Circuit 600 exploits the DC blocking-characteristics of the capacitors612, 614. DC voltages 616, 618 are impressed upon the terminals of thetwo polarized capacitors. For the purposes of this discussion, it isassumed that a symmetrical DC bias voltage is impressed. For simplicitysake, it is also assumed that capacitors 612 and 614 are equal incapacitance to one another. However, these conditions are not requiredfor the present invention. In this embodiment, the value of each DC biasvoltage is at least one half of the absolute maximum (not RMS)peak-to-zero AC voltage across the anti-series pair of capacitors. Thisis one quarter of the impressed peak-to-peak voltage magnitude. Toaccount for component variation and maintain the small signal regime,the applied DC bias voltage would be increased somewhat. The DC biasvoltages do not adversely affect the AC operation of the circuit. Thisprovides proper forward biasing, and permits continuous operationwithout the AC voltage distortion, capacitor reverse biasing, diodeforward conduction, component heat build up, DC reference voltageoscillation and premature failures characteristic of prior artapplications.

In an ideal configuration, the DC bias sources are electrically isolatedfrom (or independent of) the AC source. Accordingly, no instantaneous DCbias voltage or current will disturb the connected AC network in thisideal case. In addition, no harmonic or sub-harmonic distortion would beimparted to the AC network, by either the capacitive AC current path, orthe bias source. Moreover, this DC bias source exhibits infinitebi-directional AC impedance and zero DC resistance. Similarly, the ACcurrent path through the polarized capacitors exhibits zerobi-directional AC resistance and infinite DC resistance. The AC and DCvoltages are present in accordance with the principle of superposition.Thus the AC/DC interface causes no electromagnetic disturbance to eachother, or to adjacent electrical equipment. The polarized capacitors canbe considered to be the DC load for the DC power supply in both the ACtransient and the AC steady state case.

The simplicity of circuit 600 is informative. It serves, mainly toillustrate that polarized capacitors can be directly employed in ACnetworks, and serve as an AC voltage divider. This constitutes anelegantly simple realization of polar capacitor use in AC networks, andprovides heretofore-unknown results. There is no possible AC electricalpath but through the capacitors. Because the center node is biasedrelative to a fixed ground reference, the two alternate anti-seriesrealizations can be operated in parallel with each other, with suitablebias voltage. FIG. 6B depicts circuit 650. Circuit 650 is composed of ACsource 652, polarized capacitors 662, 664, inductor 668 and AC load 670.Inductor 668 physically separates the anti-series polarized capacitorpair 662, 664. Note that the polarity orientation and DC bias voltage ofcapacitors 662, 664 is reversed from that shown in FIG. 6A. The polaritymarks above the capacitors indicate the continuous forward biasing ofthe capacitors. One can verify that in the steady state, the DC and ACvoltages add to zero around the circuit. The steady state DC voltageacross the inductor is negligible, thus the positive nodes of thecapacitors have a virtually identical DC potential. Thus the DC junctionnode maintains continuity through the inductor. It is noted that ACsource 652 and AC load 670 similarly physically separate the negativepoles of the capacitors while remaining at the same DC potential. The ACsource 652 is coupled to the AC load 670 by the LC circuit composed ofcapacitors 662, 664 and inductor 668. LC circuits are typically used asfilters. The-circuit AC parameters such as power factor, impedance andthe like could be altered by adjustably controlling the inductance ofthe inductor. This could be accomplished by tap changing or shorting theinductor via a low resistance placed in shunt. The DC bias sourcedetails are omitted from the drawing for simplicity. This drawing servesto illustrate that AC circuit elements may separate forward biasedanti-series PECS devices in an AC application.

Circuit Implementations

FIG. 7 shows circuit 750, which uses two explicit, identical DC voltagesources 774 and 786. Each ungrounded DC voltage source positively biasesa polarized capacitor 778 and 782, respectively, through DC groundreference (AC blocking) resistor 788. Non-polar polishing capacitors776, 784, are connected in parallel across polarized capacitors 778 and782, respectively; to form corresponding capacitor sets 776/778 and782/784. An AC signal is transferred from an AC source 772 through thecapacitor sets to inductive/resistive load 790, and is conducted throughthe DC voltage sources output sections. The anti-series placement of thepolar capacitors, together with the biasing, allows their use in this ACsignal application. Both the AC source 772 output section and load 790function as steady state DC short circuits, which allows the DC sources774, 786 to bias the capacitor sets. The blocking resistor 788 providesa DC current path to the negative pole reference voltage level in thissymmetrical, ungrounded DC biasing scheme. The resistor has sufficientlyhigh AC impedance relative to the capacitors to substantially appear asan open circuit to the AC signal. This circuit embodiment servesprimarily to illustrate the use of symmetrically biased anti-seriespolarized capacitors, to transfer an AC signal. The principal ofsuperposition is explicitly portrayed. It is noted that a single,non-biased, non-polarized capacitor, from AC source 772 to load 790 canbe substituted for capacitors 776 and 784 for more effective AC signaltransmission polishing. It should be noted that the entire AC signalpasses through the output sections of the two DC power sources. The DCvoltage is divided between the capacitors and resistor 788. Note thatthe system can be arbitrarily grounded at any single node. The DC biasvoltage level can be set much higher than the AC signal size for goodsignal transfer fidelity (low harmonic distortion).

FIG. 8 depicts circuit 800, which is one embodiment of a circuit forimplementing the present invention. Circuit 800 includes AC source 805,anti-series polarized capacitors 812, 814, diode 816, resistor 817, DCvoltage source 818, and three-position switch 819. The two wings of theanti-series capacitors 812, 814 may initially be properly biasedsequentially. With the depicted circuit configuration, and the switch inthe center position (open), a durable DC bias voltage and a closeapproximation to an infinite AC impedance (an open circuit) is achieved.However, the initially charged DC bias voltage will deteriorate due tothe corona effect, and leakage currents through the capacitors. It isnoted that the two wings maintain identical bias voltages and rates ofcharge decay. Thus, by throwing switch 819 back and forth, thecapacitors 812, 814 can maintain their charge. Note that the typical ACsource is fed to the load by a transformer wind. When the circuit isengaged, and the battery switch is thrown to either wing, the biasvoltage of both wings rises with respect to the center node. The rate ofchange of the two voltages is different, but both increase. Shortly, thetwo wings have equal DC bias voltages. One, familiar with the art, caneasily verify, that the transformer wind (AC source 805) and load haveacted as a steady state short circuit, to the DC bias voltagedifference. When the switch is in a lateral position, some AC currentflows through the DC source 818 (e.g., battery). This non-ideality isunidirectional, temporary and dependent on the resistor 817 magnitude,capacitor, AC load and AC source parameters. In this case, an idealcircuit configuration works to any arbitrary degree. The switch is notnecessary for circuit operation, but is useful to illustrate theprinciple of operation, and has utility for DC voltage sourcemaintenance purposes.

Diodes in general (and diode 816 in particular) are an excellentrealization of an high AC impedance, in the case of reverse flow, whileallowing forward DC current to flow freely. Diode 816 does not block theforward AC current half wave. Switch 819 may alternately be realized asa solid-state switch or as an electromechanical device. Switch 819 canlink the DC voltage source 818 to the appropriate capacitor 812 or 814,continuously, for a given half wave, or can simply intermittentlyconnect to either side. The relatively large resistor 817 (or inductor)effectively links the DC voltage source 818 to capacitors 812, 814 whileblocking the AC signal. Other high AC impedance circuit elements canhowever be utilized. Thus, the DC bias source is composed of electricalswitch 819, DC voltage source 818, resistor 817 and diode 816. Theextremely low AC resistance and relatively low AC impedance of thecapacitors will effectively shunt the AC current. When the electricalswitch is open, the positive pole of the DC bias source is electricallyisolated from the positive terminals of the capacitors. In a typical ACnetwork, the neutral line is connected to the system ground. Thenegative terminal of the DC bias source is connected to the negativeterminal of polarized capacitors 812, 814. The DC bias source and thetwo polarized capacitors are in DC shunt with each other and maintain adifferent DC voltage level at their negative terminals than the hot,neutral and (if present) ground of circuit 800. Note that due to thepresence of transformer winds in typical AC sources, hot neutral andground wires are substantially at the same DC potential. This electricalisolation of the negative terminal of the capacitors from the AC isemphasized by the fact that neither an open circuit or dead short in theAC source and/or AC load will have any effect upon the DC bias voltageimpressed across the capacitors. Similarly a dead short may replace theDC voltage source with no effect upon the DC reference voltage level ofthe AC lines, or upon circuit operation until the capacitor chargedissipates.

FIG. 9 shows another circuit embodiment 900 of the present invention.Circuit 900 includes AC source 905, anti-series polarized capacitors912, 914, DC voltage source 926, AC blocking diode 932, AC blockingresistors 934, 935, and AC load 940. The AC neutral and/or ground pathis omitted from this drawing for simplicity. From an AC perspective,resistors 934, 935 are connected substantially in parallel acrosspolarized capacitors 912 and 914 and for small, equal resistance valuescan correct AC volt division due to capacitor component variation. Apositive DC bias is maintained across each polar capacitor with DCvoltage source 926 through diode 932 and AC blocking resistors 934 and935, which collectively function as the DC bias source. The DC biassource is substantially in shunt with the capacitors. Note that ACblocking resistors 934, 935 are substantially in AC series, and forlarge resistance values, prevent any significant AC current frombypassing the anti-series capacitor 912, 914 path. The blockingresistors 934, 935 in series combination with diode 932 preventsignificant AC current flow through the DC source 926. Any suitableresistor size, e.g., from less than 40Ω to, greater than 100 kΩ would besuitable for resistors 934, 935. Thus the DC bias source for circuit 900is composed of DC voltage source 926, diode 932, and resistors 934, 935.Additional resistance may be placed in series with the DC voltage source926 and diode 932 to decrease AC current through the source. In thesteady state, the DC voltage source 926 is substantially in shunt withcapacitors 912, 914 with respect to DC for typical component values. Theselected capacitors may require a voltage rating that is at least doublethe value of DC voltage source 926 to allow superposition of a likemagnitude AC wave across the capacitors.

If additional amps of AC current are desired, additional capacitors maybe added in parallel across capacitors 912, 914. Additional biasedanti-series capacitor banks, or series polarized capacitors joined inanti-series fashion, may also be added for increased AC current orvoltage capacity respectively. A factor that will eventually limit themaximum Ampere rating of this scheme is the bias current requirements,that is, the power limits of the DC power supply. However, there is nointrinsic limit present in this case, as DC supplies can be constructedto any arbitrary size. Also, the DC power requirements are typically asmall fraction of the AC power rating of the present invention. If DCvoltage source 926 is a voltage-regulated source, electrochemicalbatteries in anti-series arrangement may be substituted for thecapacitors 912, 914. Several battery cells in series per wing will berequired, and charge/discharge DC bias voltage windows considered, butthe realizable capacitance gain is massive. Thus with simple applicationspecific design steps, any PECS device may be adapted to use in thiscircuit.

As a practical matter, it is conventional within the art of electricalmanufacturing to separately fuse banks of capacitors. This conventionwill likely be extended to separately bias and fuse the capacitor banks.

FIG. 10 shows a circuit 1000 illustrating another use of biased,polarized capacitors in an AC network. An adaption of the circuit ofFIG. 7, circuit 1000 provides a more practical solution for general ACpower generation, transmission and distribution. Circuit 1000 comprisesAC source 1005, anti-series polarized capacitors 1009, 1023,non-polarized polishing capacitor 1011, DC voltage sources 1013, 1027,AC blocking resistors 1015, 1025, 1017, and AC load 1031. A DC biassource composed of DC voltage source 1013 and resistor 1015 issubstantially in shunt with polarized capacitor 1009. Similarly, a DCbias source composed of DC voltage source 1027 and resistor 1025 issubstantially in shunt with polarized capacitor 1023. This circuit issimilar to previously described circuits except that redundant DCbiasing sources are connected directly in parallel across the polarizedcapacitors. This circuit has utility in general AC applications. Largeimpedance (Ω−kΩ) biasing (AC blocking) resistors 1015, 1025 allow DCbiasing to occur while appearing as an open circuit for AC purposes. Aninductor (or other AC open circuit device) may replace the biasingresistors 1015, 1025. The large (kΩ−MΩ) blocking resistor 1017 may bereplaced by an open circuit. Similarly, blocking resistor 1017 may berelocated between the center nodes of the DC sources and the PECS devicecenter node.

FIG. 11 illustrates a capacitive power coupling arrangement 1100utilizing a single electrically isolated DC power supply 1115 to providethe necessary, symmetrical, active DC bias voltage for continuousoperation of polarized capacitors in a general AC network application.Circuit 1100 generally includes AC source 1105, anti-series polarizedcapacitors 1112, 1114, DC voltage source 1115, blocking diode 1117, biasresistors 1119, 1121 and AC load 1130. Electrically isolatednon-regulated DC voltage source 1115 is composed of an isolationtransformer, full wave Diode Bridge and an output section of twoinductors and a polarized capacitor 1124. The DC bias source consists ofDC voltage source 1115, diode 1117, and resistors 1119, 1121. Anoptional and unnumbered resistor is shown in the DC bias source negativeleg. The bias resistors 1119, 1121 and diode 1117 provide high ACimpedance while allowing a satisfactory DC charging current to thepolarized capacitors 1112, 1114. Diode 1117 further prevents a back flowof DC current in the event of diode bridge failure in the DC powersupply. The DC power supply output section consisting of inductors 1122,1123, capacitor 1124 as well as diode 1117 may be omitted withoutcompromising function. Capacitors 1112 and 1114 constitute the steadystate system DC load and are in shunt with respect to DC, but are inanti-series with respect to AC. The isolation transformer turns ratiowithin the DC power supply sets the DC bias voltage level and isoperably connected to the AC source 1105. It is noted that the DCreference voltage level of nodes A and B are substantially at the ACsystem ground, while node D is held below ground by the DC bias source.The electrical isolation of the DC voltage source from the AC sourcewould allow either orientation of capacitors 1112, 1114 to be used. Thatis the capacitor positive poles could be connected at node D, providedthe bias power supply polarity is reversed. In that case, the node Dreference DC voltage would be above the AC system ground level.

The power delivered to the AC load may be many orders of magnitudelarger than the power requirement of the biasing power source. The ACsource 1105 is assumed to include one or more inductive winds, e.g.,from a generator or transformer. This provides a steady state DC shortcircuit. The superimposed AC wave and DC bias voltage should be lessthan the capacitor rated DC voltage, yet maintain positive biasing atall points in the AC voltage waveform. The magnitude of the DC biasvoltage significantly exceeds the impressed AC voltage waveformmagnitude to reduce harmonic distortion of the AC signal. The referencevoltage level at point D, representing the negative capacitor poles, ismaintained below ground in the single-phase AC system shown. It shouldbe noted that the magnitude of the DC leakage current through thecapacitors is minuscule. The DC voltage level of the AC source and ACload is taken to be virtually identical to the AC system ground. Thus,the polar capacitor negative connections are below system ground in thisrealization. In addition, the polarity of the capacitors and DC biassource can be simultaneously reversed. This reversal would raise thepolar capacitor positive poles above the ground reference but has nosignificant first order effect upon the AC power transfer. Moreover,multiple, parallel, circuits with unique (or alternatively, a commonbiasing voltage) can be employed. This demonstrates that negligiblesteady state DC biasing of the AC circuit occurs. The selection ofanti-series orientation selection may be related to capacitor casegrounding, safety, convention, cooling, transfer function and othersecondary considerations and issues.

The resistor 1119 connecting to node C, the resistor in the negative DCleg and resistor 1121 provide instantaneous symmetrical DC biasing ofthe capacitors. It is noted that typical inductive and resistive ACloads and sources provide a DC short to the system ground. It isphysically allowable to place the AC load, or alternately the AC sourcebetween the polarized capacitors. It is preferred that both sides of aload on/off switch (not shown) be resistively connected to the DC biassource in this realization. This configuration provides a method foroperating the AC source and AC load at different DC ground referencepoints. It is noted that until the resistors are connected to nodes A, Dand C, the DC bias voltage source is completely independent of the ACsystem ground at node B. This is due to the AC isolation transformer andthe full wave Rectifier Bridge. The necessary condition of continuous DCbiasing can be supplied with half wave rectification, but ½ fundamentalfrequency harmonics are then injected into the AC network.

An electrically isolated regulated DC power supply with or withoutbattery can be employed where desirable. Similarly, the bias voltage canbe coupled to the polarized, AC signal carrying capacitors withinductors or other low DC resistance, high AC impedance circuitelements. The output section of the DC voltage source 1115 as well asdiode 1117 may be eliminated, allowing resistors 1121, 1119 andcapacitors 1112, 1114 to serve as a simplified output section.

FIG. 12 illustrates circuit 1200, which generally shows a three-phase,three wire AC system incorporating an embodiment of the presentinvention with the DC biasing details omitted. Circuit 1200 includesthree-phase source 1201 (shown in a Delta configuration), forwardlybiased anti-series polarized capacitor pairs 1209A-1209C, and athree-phase AC load 1211, which includes loads 1211A-1211C. For aproperly biased, high AC impedance biasing system, this is anappropriate engineering approximation. The AC parameters of the biasedpolar capacitor assembly are sufficient for AC circuit analysis. It isclearly unnecessary to show DC details in AC circuit models for thispurpose. FIG. 12 is thus a three-phase version of FIG. 6A with the biasvoltage indications omitted. The known characteristic of DC voltageblocking in capacitors renders biasing details unnecessary for ACcircuit analysis. If desired, however, the DC bias voltage level of thesystem can be noted for safety and maintenance purposes. Note that thisis shown as a series application. If the AC load shown is a currentlimiting device such as a 3Φ resistor then this combined load becomes ashunt power factor correction device for other AC loads on either sideof the source transformer. This device can be hard-wired orcontrollable. If the indicated load performs useful work, then powerfactor correction is accomplished without an increase in system Wattage.Any circuit capacitance constructed according to the process describedherein will substantially exhibit terminal characteristics of anon-polar capacitor as seen from the AC source. The schematic is thusspared unnecessary detail in design, analysis and trouble shooting. Thedetails of the polarized capacitor implementation can be referred to asnecessary. An alternate schematic with reversed curves and lines couldbe used to show opposite capacitor alignment if desired. Otherpolyphasic configurations, including nine phase and the like can besimilarly represented. It is noted that one could omit a capacitorantiseries pair, such as 1209B in the event network operating parametersrequired it. The negative poles of capacitors 1209A, 1209C could stillbe biased below the level of the AC source and loads.

FIG. 13 shows a 3 phase, four-wire AC system with a 3 phase,electrically isolated, unregulated, DC power supply for capacitorbiasing. The three phase DC power supply (DC voltage source) 1301 isused to forwardly bias polarized capacitor pairs 1309 pursuant to thepresent invention. Power supply 1301 generally includes transformerprimary 1302A, transformer secondary 1302B, Diode Bridge 1303, chokes1304 and 1305, and polarized capacitor 1306 and diode 1307 in thisexample. The DC power supply together with resistor 1308, the diodesassociated with nodes 4-10, and the diode, resistor combinationsassociated with nodes 1-3 comprise the DC bias source. Diode Bridge 1303is a three phase, six pulse, full wave device. Diode/resistor serieselements connect the DC power supply negative leg respectively topolarized capacitor center nodes 1, 2 and 3 as shown. The DC powersupply positive leg is connected via resistor 1308 and diodes 1310(diode #s 4-10) to polarized capacitor nodes 4-9 and to the systemneutral wire 10. The anti-series diodes 4 and 7 block AC current fromthe A leg, while DC biasing the anti-series capacitors through the abovelisted center node 1. The B leg and C legs are similarly DC biased. ACcurrent is fed from the source to the load through the DC biasedanti-series capacitors in the A, B and C legs. As shown the A, B and Clegs of the AC source simultaneously feed the capacitors and thetransformer primary. The vast majority of the AC power is delivered tothe AC load. Other, polyphasic AC system capacitor coupling circuitrymay be similarly realized. As indicated previously, the illustratedrealization of the bias DC power supply is arbitrary. Particularapplications may require alternate DC power supply realizations foroptimal long-term performance. Typically in AC systems, neutral node 10would be grounded at a single point via a hard ground, groundingresistor, inductor or capacitor. Note that the design electricalisolation characterizing DC voltage source 1301 loses some effect whenconnected to the AC source, polarized capacitors, AC load and systemground if present.

The primary side Delta transformer winds 1302A and the AC source (Wye,Scott Tee) winds provide redundant paths and mandate a unified systemsteady state DC reference voltage at nodes 4-10. Inductors 1304, 1305,diode 1307 and resistor 1308 prevent conduction of system (block) ACcurrent through the DC power supply. The PECS device center nodes 1, 2,3 are held at a lower DC potential by DC source 1301 providing for asubstantially uniform PECS device DC bias voltage. This DC bias voltagemagnitude is unaltered by the AC system grounding convention. Note thata single DC source is biasing the three PECS device pairs shown in 1309.These capacitor pairs are substantially in DC shunt, yet are in threeseparate AC legs. In fact, each wing of each capacitive pair issubstantially in DC shunt with DC source 1301.

FIG. 14 shows an alternative three phase, four wire AC system with athree phase, ungrounded, unregulated, DC power supply 1401 for biasingpolarized capacitors 1409. In place of a diode manifold (1310) aresistive manifold 1410 is instead used in the illustrated embodiment.In a standard engineering approximation, order of magnitude differencesin impedance are functionally similar to the previous circuit. Thecapacitive AC impedance is low, so that 500[Ω] AC resistors will exhibitessentially the same terminal behavior, in a 120:208[VAC], 60 Hertzsystem as the AC current blocking diodes of the previous circuit. Thiscircuit exploits the milliOhm (mΩ) ESR of the capacitors in shunt withthe 500[Ω] resistor connected nodes 1-10 to effectively direct the ACcurrent through the capacitors rather than the DC circuitry under theconvention that electricity follows the path of least resistance. Allthe components shown except 1409 compose the DC bias source in thisexample. An alternate method of biasing is used to illustrate that manysuch high AC impedance biasing schemes may be constructed to accomplishthe ends of the invention.

FIG. 15 illustrates an alternate inductive method of biasing thepolarized capacitors previously shown in FIG. 13 and FIG. 14. FIG. 15 iscomposed of series AC source, load and antiseries capacitors labeled1509, three discrete three phase inductor coils and DC voltage source1501. The DC voltage source positive leg is connected to output diodesP1 and P2, while the negative leg is connected to current limited diodewith output N1. Along these lines, it should be clear to those, familiarwith the art that many additional biasing schemes are suggested herein.Note that output N1 is connected to the polar capacitor negatives viainductors at nodes 1-3 while P1 and P2 are connected to the capacitorpositive poles 4-9, in this three phase, three-wire (delta) AC systemlabeled 1509. Series resistive elements in the DC path may be added tofurther reduce AC current through the DC source. Also note that therectifier isolation transformer is omitted from the schematic forsimplicity. Properly selected, high impedance inductors or transformercoils can thus be used to couple the DC voltage source to the polarizedcapacitors while providing AC blocking utility.

This phenomenon gives rise to a caution. A magnetic coil or smallresistance, placed across a DC bias voltage creates a short. This maycause a destructive, reverse voltage condition across the polarizedcapacitors if care is not taken. Reverse polarity hazards are well knownto those familiar with the art. For this reason, the normal courseshould be to use the polarized capacitor assembly as a unit. High pass,low pass, band pass and blocking filters, tied to the center node,should be attempted with extreme caution for these same reasons.

Recall that motors and transformers have integral coils. Further recallthat energy conversion equipment typically includes isolationtransformers. Consider a distribution level transformer operating one ormore AC motors, through the present invention, and other equipment inparallel. In this common case, inductor coils and resistor paths arepresent, on both the source and load sides of the capacitor bank. Thisis true for the hot lines for Wye, Scott Tee, High Leg Delta, Open Deltaand Delta type connections, and for the neutral lines in the first threecases only. Also note that prevailing grounds in AC power systems are ofthe solid, resistance or inductive types. In the normal steady stateoperating mode, we thus have redundant DC bias paths to the conductorsin typical single phase and polyphasic electrical networks. The internalnodes of the capacitor bank may be redundantly connected; however, dueto the above condition, this will seldom be considered necessary for theexternal nodes.

FIG. 16 illustrates circuit 1600, which provides an implementation ofthe present invention suitable for a 120:240[VAC] single-phase system.This is the most common household AC power distribution scheme used inthe United States. Note that an anti-series capacitor assembly 1609 ispresent in each hot leg, though a neutral assembly could be included.The capacitor assembly DC junction nodes are biased below system ground.The details of the DC power supply and AC current blocking are omittedfrom the schematic for simplicity. The AC system ground, neutral and hotlegs are equi-potential surfaces with respect to steady state DC.Polarized capacitors are available with discrete AC ripple currentratings. Parallel capacitors or capacitor assemblies may be required torealize arbitrary AC current ratings. Transient (impulse & surge) and/orsteady state current parameters may be used to determine the number anddesign of polar capacitors required in a given application. FIG. 16shows a parallel assembly of capacitors constructed with each internalelement in shunt. The parallel connections may be hard-wired orcontrollable. The AC loads for such an application may be powered by twoor three wire 120 VAC, or by two, three or four wire 240 VAC. The centerwind of the transformer and the load neutral wire is solidly grounded inthis circuit.

Network parameters and goals such as resonance may be accomplished byswitching in and out of banks of capacitors. This switching may beaccomplished manually, electro-mechanically, or by solid-state means. Inmany cases, (including without limitation aluminum electrolyticcapacitors), capacitance, series resistance, AC impedance, service life,dissipation factor and the like, may also be controlled by means ofambient and core temperature regulation. These capacitor parameters andcapacitor life expectancy vary with core temperature and can be tunedsomewhat by deliberate temperature variation.

It is desirable to maintain proper DC biasing of parallel units. It isalso advantageous to provide high AC impedance and low DC resistanceconnections around the switching mechanism in the case of controllableswitching units. Note also that the source transformer provides aredundant DC bias path to each branch of Circuit 1600, except for the DCjunction nodes. The circuit of FIG. 16 can be made less susceptible tocascade failure by separately fusing the DC bias path to the wings andcenter nodes, as well as the AC path of each PECS device in the 120[V]legs of the 240:120[V] output. The circuit of FIG. 16 may further beconverted to an AC current divider circuit by separating the outputsand, if desired the center nodes.

FIG. 17 shows a simple representation of a high voltage realization of a4n+ polarized capacitor and biasing circuit 1700. Circuit 1700 generallycomprises AC source 1701, anti-series polarized capacitors 1702-1705 andAC load 1716 as well as the DC bias circuitry. The DC bias sourceconsists of resistors 1706, 1707, 1708, 1713, 1714 and DC voltagesources 1709-1712. Capacitors 1702, 1703 are in series, as arecapacitors 1704, 1705. Capacitor pairs 1702, 1703 and 1704, 1705 arejoined in an anti-series AC configuration. They are also substantiallyin DC shunt with one another. Thus the DC charging current, leakagecurrent and bias voltage see parallel, two-capacitor configurations. TheAC signal however passes through what is effectively a seriesconfiguration of 4 capacitors. This point is significant indetermination of maximum capacitor voltages when taking componenttolerance or error into account. This system can be extended to allowthe construction of 6n+, 8n+ and higher voltage AC capacitors usingpolarized capacitors. It is noted that overall symmetry is maintained.In this particular implementation, the biasing voltage is explicitlyexternally divided. This is not essential but is illustrative only ofone bias method. As is the case with other capacitor classes and types,the capacitors intrinsically act as a volt divider for both AC and DCwithin component error. A single DC voltage source or two DC voltagesources may be substituted with appropriate AC blocking devices andbiasing considerations. Distribution resistors may be configured toprovide suitable DC bias voltage division and improved AC voltagedivision across capacitors 1702-1705. This resistive biasing network canreduce the effects of capacitor component tolerance differences. ACnetwork impedance, capacitance, equivalent series resistance and thelike can be altered via the switching in or out of one or morecapacitors in series or parallel. Aluminum electrolytic capacitor cases,as typically constructed for heat dissipation reasons, may be at thevoltage of the negative pole, rather than system ground, a matterrequiring a degree of caution. One other area of interest is that anexploitable asymmetry is present with respect to volt division of AC andDC. Scanning from top to bottom, three forward biased conditions exist.Like amounts of biasing conditions exist from bottom to top. Note thatthe same end of AC voltage sharing may be accomplished by twoindependent antiseries configurations of PECS devices as accomplished inthis circuit with an anti-series configuration of series capacitors perwing. This alternate method provides for a lower DC bias voltage sourceand comprises a more extensive example of the principle of AC seriestopography concurrent with DC shunt topography. An example of theusefulness of the above observation, is that twenty five percent of theAC voltage impressed across the capacitor bank is present across anygiven capacitor. Within component tolerances and/or error, one canmonitor the impressed AC voltage at a reduced voltage, and anyelectronics requiring biasing can be directly employed.

Series implementations of capacitors are avoided where possible inconventional electrical design. The primary reason is that two identicalcapacitors in series will exhibit half the capacitance of a singlecapacitor. This is a damning situation, with currently available ACcapacitor technologies, due to the low level of capacitance economicallyrealizable. This phenomenon is however insignificant, with the presentinvention. AC ripple current is normally the limiting parameter, of thepresent invention, rather than capacitance. The present inventionprovides an overabundance of capacitance herein via the use of PECSdevices.

FIG. 18 illustrates yet another realization of a circuit 1800 of thepresent invention. Circuit 1800 uses a variable DC voltage source 1801,whose value is proportional to the AC voltage across anti-seriescapacitor pair 1809, for forwardly DC biasing capacitor pair 1809. Thisensures that anti-series capacitor pair 1809 remains sufficientlyforwardly biased based on the size of the applied AC signal. The primaryside, of the small isolation transformer shown; is energized by thevoltage, across the mechanically anti-series capacitor assembly 1809.Note that the transformer primary side acts as a DC short to thecapacitor positive poles. As discussed elsewhere herein, any inductorexhibits this physical characteristic. A primary to secondarytransformer ratio of between 1:1 and 2:1 is suitable for 1Φ or 3Φimplementations of the depicted circuit. A full wave diode bridge, withfilter, is coupled to the secondary side of the transformer. Theelectrically isolated, filtered output is then snubbed into theanti-series capacitors as a DC voltage supply. Resistor 1803 and diode1802 serve as an AC blocking device and a DC bias connection from thecapacitor DC junction node m to the negative pole of the DC voltagesupply. As the capacitor AC voltage drop (impressed voltage) increasesthe DC bias voltage will increase. If the AC voltage drop across thecapacitor decreases, the bias voltage will begin to slowly decay. Thus,this configuration has a feedback feature, and dynamically responds to aneed for an increased DC bias voltage. A loading resistor 1804 is shownin shunt with the AC load. This is a pre-loading resistor and is widelyused to improve voltage regulation, by those who are familiar with theart. This bias of FIG. 18 can be used to provide continuous forward biasfor both capacitor wings. It is suitable for handling transient ACsystem resonant biasing requirements if the component ratings areappropriate. Various implementations may include resistance in thepositive DC bias leg. Note that in many applications a redundant DC biassupply may be desirable. An effort to reduce component count is anobject of the electrical design of FIG. 18. An analogous system may beconstructed wherein DC electrical isolation is provided by capacitors.

FIG. 19 shows a capacitor AC induction (or split phase) motor using aPECS device implementation of the instant invention. AC source 1904,switch 1902, PECSD pair 1903, and motor (stator) winds 1900, 1901 areshown. DC bias circuitry and rotor details are omitted. Motor wind 1900is connected to forwardly DC biased anti-series capacitor assembly 1903.Motor (stator) wind 1901 is in shunt with the 1900, 1903 assembly.Switch 1902 is closed to connect the AC source 1904. Split phase (and/orcapacitor AC induction) motors provide starting torque and a rotatingfield. The series combination of 1900, 1903 produces a unity or slightlyleading power factor. This will cause the currents through coils (motorwinds) 1900 and 1901 to be out of phase by approximately 90°. There isno need to disconnect the motor wind 1900 in that the instant inventionis suitable for continuous duty. This 90° phase shift can cancel orreduce the 120-Hertz mechanical vibration (pulsation) characteristic ofsingle-phase motors. Alternately the motor wind 1901 can be disconnectedfollowing startup. Either method can be used to configure a circuit,which is arbitrarily close to resonance during steady state and/orstartup.

FIG. 20 shows tuned resonant series LC circuit 2000, composed ofinductor 2001 and PECS device pair 2002 of the instant invention. Solidstate (single sided static) switch 2003 composed in this drawing ofanti-parallel thyristors (SCRs) is in shunt with 2002. Resistor 2004depicts the steady state load. Series and/or parallel combinations ofinductors and capacitors are typically referred to as LC circuits in thetrade and are widely used for filtration purposes. DC bias details areomitted for simplicity. When a circuit fault condition is established bythe closing of switch 2005, the current detector (torus) 2006 detects arapidly increasing current. Alternately, a voltage sensing mechanism,ground fault detection or alternate methods can be employed to detectnetwork fault conditions. This signal is operably connected to the solidstate switch, via commercially available circuitry. When the staticswitch shorts the PECS device 2002 of the instant invention, theresonant band pass circuit of 2002 becomes profoundly inductive andcurrent limiting. Commercial solid state switch response time issub-cycle. Note that a switch similar to 2003 might be placedsubstantially in shunt across inductor 2001. This would provide theability to tune steady state AC network parameters by shorting out theexcess inductance. Similar tuning and detuning mechanisms may beconstructed for shunt LC circuits and hybrid designs.

FIG. 21 depicts assembly 2100, which includes four polarized capacitors2101 through 2104 mechanically suspended by non-conducting verticalstrips 2111 and 2112, connected to conductors 2107, 2108. Capacitors2101 and 2102 are in shunt via negative post conductor 2105 andconducting heat exchanger 2107, as are capacitors 2103 and 2104connected by conductors 2106 and 2108. Positive pole capacitor busingand bias circuitry details are omitted for simplicity. For this examplepolarized capacitors with integral base bolts are selected for theirheat conduction capabilities. Conductor 2107 is at essentially the samepotential as conductor 2105 and the cans 2101, 2102. Similarly 2108 and2106 and cans 2103, 2104 are at a virtual short in most commerciallyavailable large can electrolytic capacitors. The liquid dielectric (oil)level is above the conductors 2107 and 2108 for heat dissipation withoutthe requirement of electrical connection considerations. The oil levelmay be raised above the capacitor cases to maximize electrical touchsafety if dry connections and clear capacitor pressure vents aremaintained. Mechanical tubing of a simplified external heat exchanger2109 is shown. The simple design reveals a method of providingelectrical isolation and temperature regulation for the steady stateoperation of PECS devices. The life expectancy of PECS devices and thecapacitive parameters can be varied by the adjustment of the oiltemperature. Electrical safety is provided by the insulatingcharacteristics of the liquid dielectric and the insulating fasteners.The term ‘liquid dielectric’ is not intended to exclude insulation andheat regulation via gaseous or solid dielectrics with temperatureconduction, convection, radiation and/or phonon transmission capability,and is illustrative rather than limiting. Various insulating fasteningmechanisms and methods of maintaining good electrical contact in oilbaths are familiar to those in the trade. An insulating cap, boot, seal,sleeve or vent exhaust tube and/or dry connection methods and productssuch as ‘chico’ and silicon are examples. This same end of enhancedcooling and electrical safety may be accomplished by increased airflowin a touch safe enclosure such as ingress protection IP-20 insidespecifications. Integral heat exchanger designs may be used at 2107,2108 and the enclosure to further enhance heat transfer efficiency. Notethat the external heat exchanger 2109 may be connected to variousheating and/or cooling mechanisms, such as water baths or heat pumps.The preferred implementation varies with the device power level, ambienttemperature, optimal capacitor parameters, touch-safety and likeconsiderations. In addition PECS devices and PECS device combinationsmay be constructed with multiple electrical polarities exposed to humantouch for heat conduction reasons, via the can or alternately via heatexchanger enhancements. These designs add to the touch-safety issues,and further increase the utility of temperature regulation incombination with electrical contact safety considerations. Variousmanufacturing techniques employing ‘can within a can’ designs, variousstates of matter, mass transport and the like are expected to havesignificant utility in heat regulation for implementations of theinstant invention. Similarly, direct insertion of a heat exchangerelement into the capacitor case is feasible when electrical insulationdesign considerations are employed.

FIG. 22 shows circuit 2200 composed of AC source 2201, autotransformer2202, resistor 2203, rectifier 2204, switch 2205, polarized capacitors2206, 2207 and AC load 2208. Autotransformer 2202 adjusts the system ACvoltage to the charging circuitry composed of resistor 2203 and diode2204 at other than the system AC voltage. An optional loading resistor2209 connects capacitor 2206 to the charging circuitry. The chargingcircuitry will maintain the polarized capacitors at any arbitrary DCbias voltage until the load is engaged. It is also possible to achievecontinuous operation capability by the use of a half wave or full waveRectifier Bridge and other such methods. Alternate methods of achievingelectrical isolation suitable for maintaining a continuous DC biasvoltage across the polarized capacitors may be used. This system may beredesigned to provide DC electrical isolation by connecting theautotransformer to the AC power supply via two capacitors. It is furthernoted that the two capacitors may be an anti-parallel set of PECSdevices. This method has capabilities in energy conversion applicationssuch as rectifiers and inverters. The circuit may be self-biasing, thatis without the requirement for control circuitry. This circuit primarilyillustrates the use of an autotransformer in bias circuitry to achieve aselected bias voltage level. One may include tap changers, controlledrectifiers and the like to regulate the DC bias voltage level.

FIG. 23 shows AC source 2301, polarized capacitors 2302, 2303,controllable rectifier 2304, current limiting resistor 2305, loadingresistor 2306, switch 2307 and load 2308. The controllable rectifier,such as an IGBT, transistor, cut off SCR or the like can be gated on oroff to control the level of DC bias voltage. Half wave rectification iscaused when AC current flows through capacitor 2302, rectifier 2304 andcurrent limiting resistor 2305. The high impedance pre-loading resistor2306 may be omitted. This circuit has the capability to build up andmaintain a regulated capacitor bias charge, without over charging thecapacitors. The details of the rectifier control circuitry are omitted,as such control circuits are available commercially and the designtechniques are familiar to those in the trade. It is noted that thisconfiguration will operate in the small signal regime, and is of use intransient and/or steady state operation. It is further noted that anuncontrolled rectifier (diode) can be substituted for 2304. The circuitwill establish and maintain a DC bias voltage across capacitors 2302,2303 substantially equal to the peak to zero voltage magnitude of ACsource 2301. The steady state DC current through resistor 2305 isessentially equal to the DC leakage current of capacitors 2302, 2303.

FIG. 23A depicts a simplified circuit 23 to more clearly reveal thecharging mechanism. The circuit elements are reordered to cut to thechase. When the controllable rectifier 2304 is gated on, one half wave,or a portion thereof causes a rectification current and charge build upacross the capacitor 2302. Resistor 2305 or a similar device serves toreduce the transient (DC bias charging, half wave) current, and leavesthe load (not shown) engaged. No significant steady state AC currentflows through resistor 2305.

FIG. 24 shows AC source 2401, zener diode 2402, diode 2403, polarizedcapacitors 2404, 2405, blocking diode 2406, blocking resistor 2407,optional resistor 2408, switch 2409, AC load 2410 and inductor 2411.This is a non-controlled version of the circuit of FIG. 23. The zenerdiode 2402 in anti-series with the diode 2403 and inductor 2411 willlimit the capacitor bias voltage without the use of control circuitry. Aportion of the excess DC bias voltage is conducted and dissipatedthrough the zener diode 2402, diode 2403 and inductor 2411. It is notedthat this configuration may sacrifice the ability to operate in thesmall signal regime, depending on selected component values. Also notethat inductor 2411 may be replaced with a resistor or other suitable ACblocking, DC dissipating component.

FIG. 25 shows circuit 2500, consisting of AC source 2502, polarizedcapacitors 2512, 2514 and AC load 2520. Also shown is DC bias sourcecomposed of resistors 2503, 2505, 2507, 2509, diode 2521 and DC voltagesource 2522 which functions even when the AC source or load are switchedout of the circuit. The DC bias source establishes and maintains aforward bias voltage across the capacitors 2512, 2514. The resistors2503, 2505, 2507, 2509 and diode 2521 will evenly distribute the DCvoltage across the capacitors and prevent any significant AC currentfrom bypassing the capacitors. It is noted that any single node of thiscircuit may be operably connected to a system ground. In thisillustration, the AC load and the AC source will operate at different DCreference voltages.

Among other things, this circuit drawing illustrates that aconfiguration of anti-series PECS devices (polarized capacitors 2512 and2514 in the drawing) can have more than one DC junction node. A first DCjunction node, which includes AC devices 2507, 2509 at the positivecapacitor connections, is coupled to the AC load, and a second DCjunction node, which includes AC devices 2503, 2505, at the negativecapacitor connections is coupled to the AC Source. The circuit furtherreveals that the capacitor orientation may be arbitrarily depicted aspositive to positive, negative to negative, or with separating ACdevices without having a first order influence upon AC power transfer inan ungrounded application in that the DC considerations have littlerelation to AC power transfer.

FIG. 26 depicts circuit 2600, composed of AC source 2602, AC load 2622,and polarized capacitor pairs 2604, 2606 and 2608, 2610. The associatedDC bias circuitry is powered by DC voltage source 2618 and conducted byseries diode 2621 and series resistor 2619 and the associateddistribution resistors 2605, 2615, 2603, 2607, 2609, 2611, 2613, and2617. It is noted that resistors 2605, 2615 maintain a uniform DCvoltage at the positive DC nodes of capacitors 2604, 2606 and 2608,2610. Similarly the negative DC nodes of the capacitors are held at acommon DC reference voltage by resistors 2603, 2607, 2609, 2611, 2613,2617. Diode 2621 and resistor 2619 serve to block AC current frompassing through the DC voltage source 2618. Point A shows the connectionpoint to the upper bias circuitry. Properly selected resistor values mayserve to reduce the effects of capacitor component variation in AC voltdivision. Circuit 2600 illustrates the use of a single low DC voltagesource to bias two anti-series polarized capacitor pairs, which arearranged in a series fashion. Each of the capacitors is arrangedsubstantially in DC shunt with the DC voltage source and the othercapacitors. It is apparent that three or more anti-series capacitorpair, in a series configuration could be similarly biased by a singlelow voltage source with an appropriate bias voltage distributionnetwork.

FIG. 27 shows circuit 2700 including AC source 2702, isolationtransformer 2704, and anti-series polarized capacitors 2706, 2708. Alsoincluded is a DC biasing source composed of thyristor bridge 2709-2715,coils 2717, 2719, bias resistors 2723-2729 and filter capacitor 2721connected to the positive voltage pole of capacitors 2706, 2708 via nodeX. Not shown is a similar AC blocking connection of the DC negativeoutput to the negative poles of capacitors 2706, 2708. The rectifiedoutput wave is filtered by inductors 2717, 2719 and polarized capacitor2721 and conducted to DC load 2730. A small portion of the available DCpower is used to forwardly bias capacitors 2706, 2708 when appropriateAC blocking devices connect the capacitor negative poles to the DCvoltage source negative pole. This configuration illustrates the DCblocking feature of polarized capacitors in an AC application. Alsoshown is a method of putting the produced DC voltage to use in a commonapplication, that of a battery charger or DC power supply. Theanti-series capacitors are used to provide a DC voltage supply forgeneral utility purposes. Alternately a separate DC bias source may beused to forwardly bias the capacitors.

FIG. 28 reveals circuit 2800. Circuit 2800 is assembled from three phaseisolation transformers 2802, 2814 polarized capacitors 2804, 2806, 2808,DC source 2810 and resistor 2811. Polarized capacitors 2804, 2806, 2808are in an antiseries configuration analogous to the single-phasecircuits of FIGS. 25, 27. The appropriate forward bias voltage isimpressed across capacitors 2804, 2806, 2808 through the DC junctionnodes that incorporate inductors 2802, 2814. The DC bias source consistsof an electrically isolated DC voltage source 2810 and series resistor2811. The DC bias source is directly in shunt with capacitor 2808 andsubstantially in DC shunt with capacitors 2804, 2806. The inductor(transformer winds) on the prime side of 2802 impresses the positive DCbias reference voltage to the positive sides of capacitors 2804, 2806.Similarly the transformer wind of 2814A (the non-prime side) connectsthe negative capacitor poles to the negative pole of the DC bias source.Redundant DC bias sources may be used to increase design robustness.This drawing teaches a DC shunt arrangement using a single polarizedcapacitor in each hot leg of a polyphasic AC system. As shown thissystem is compatible with, but does not require a single point groundfor operation. A similar wiring arrangement could be used in a motorgenerator combination. This circuit further teaches a polyphasic ACanti-series configuration and method for continuous forward DC biasing.

FIG. 29 shows circuit 2900, which is a single-phase 240:120 VACsingle-phase network commonly used in U.S. residences. Circuit 2900 iscomposed of AC source 2902, AC source transformer 2904, polarizedcapacitors 2906, 2908, 2910, DC source 2913, AC blocking resistor 2911and AC loads 2912, 2914, 2916, 2918. The capacitor antiseriesarrangement in circuit 2900 is composed of a single polarized capacitorin each leg. The DC bias source composed of DC voltage source 2913 andAC blocking resistor 2911 is in shunt with polarized capacitor 2910 andsubstantially in shunt with polarized capacitors 2906, 2908 by way ofthe transformer winds and AC loads. Note that AC loads 2912, 2914 arepowered by 120 VAC, load 2916 by three wire 120:240 VAC and 2918 ispowered by two wire 240 VAC. This circuit illustrates an alternateanti-series capacitor configuration than shown in FIG. 16. Note that thesource transformer secondary or the neutral node connected to thepositive pole of capacitor 2908 and loads 2912, 2914, 2916 may begrounded. Note that in this configuration, both sides can not besimultaneously grounded. The ground loop would short the DC biasvoltage. Note that AC circuit elements separate the polarized capacitorsin this antiseries PECS device configuration and act as steady state DCshort circuits. This teaches another example of a DC junction nodeincorporating AC circuit elements within the DC capacitor coupling.

FIG. 30 shows circuit 3000, a single phase AC circuit using a singlediode to establish and maintain the DC bias voltage impressed across ananti-series capacitor pair. Circuit 3000 is composed of AC source 3001,source transformer 3003, antiseries capacitor pair 3013, 3015, AC load3020, and DC bias circuitry including polarized capacitor 3005,rectifier 3007 and resistors 3009, 3011. Rectifier 3007 and resistors3009, 3011 will charge capacitors 3005, 3013, 3015 and substantiallyblock AC current in the steady state. Details of the connection betweenresistor 3011 and AC load 3020 are omitted for simplicity. The DC powersupply is suitable for continuous operation but does not provide fullwave rectification. The small steady state DC power requirements of thepolarized capacitors render this a very useful and economic design. Theprimary side of AC source transformer 3003, and AC source 3001 will ofcourse see no DC from the secondary side. The reflected harmonics due tohalf wave rectification will cause little AC source difficulty due tothe tiny steady state bias power load relative to the AC load. FIG. 30teaches a simple circuit implementation suitable for continuousoperation.

Design Considerations

A primary design consideration is the selection of polarized electricalcharge storage (PECS) device technology and configuration. The DCvoltage range constraints must be considered in detail. For exampleindustrial nickel-cadmium (Nicad) electrochemical batteries have anominal voltage of 1.2 Volts per cell. The cells may operate withequalize charging and final discharge voltages of 1.7 and 1.0 Volts percell respectively. The design voltage range would typically be 1.05-1.5Volts per cell. The number of battery cells selected would then beconsistent with the component and/or system AC voltage and/or resonantAC voltage as appropriate. The AC ripple current allowed by the batterycells would be used to determine the number of parallel battery cellsand/or strings required for the AC application. A regulatedbattery-charging device would then be selected to appropriately maintainthe electrochemical battery in a charged state. Each polarizedelectrical charge storage device, or combination of devices wouldrequire analogous DC system voltage design steps that are familiar tothose knowledgeable in the trade. A more detailed description of designsteps for aluminum electrolytic capacitors is provided herein.

Waveform transfer fidelity is important, and is enhanced markedly bystaying within the small AC signal regime. The instant invention isconfigured to stay within this regime to any arbitrary degree.

The typical limiting design parameter, of the present invention, incircuit applications is the allowable AC ripple current. Both steadystate current and transient load current should be considered. Theripple current can be considered, for most purposes, to be the allowabledisplacement current, in the present invention. Computer grade,capacitor nominal data is based on 120 Hertz. The frequency response,ripple current, de-rating factor, for a typical computer gradecapacitor, operating at 60[Hz] is 0.8. The present invention providesabundant capacitance to spare. Thus, it is possible to reduce the ACcurrent through a given capacitor to any arbitrary value. This isaccomplished by the simple expedient of increasing the number of polarcapacitor assemblies in parallel. The shunt capacitors will furtherdecrease the AC impedance and can be used as a load voltage-regulatingmechanism when adjusted in real time.

A circuit design parameter to consider is AC current carrying capacity.The transient demands of the application should be considered the key toa successful application of the present invention. Transformer inrushcurrents and motor starting currents are a major consideration in sizeselection of biased polar capacitors with the instant invention. Asecondary, and related consideration, is the series impedance of thecapacitor bank. Heat generation due to I² R losses is paramount tocapacitor life. Excessive heat build up is destructive to the polarizedcapacitors and/or other PECS devices. One typically need not considerthe capacitance of the device as a sizing parameter.

Many applications are three phase, or single phase, 3 wire systems. Thussome lack of clarity may ensue as to appropriate design steps. A singlecapacitor per leg would be relatively clear, but for an anti series pairor configuration in each leg would have differing inter-device andintra-device voltages. For example, in the 120:208 VAC scheme, aninter-device leg to leg, (LL) fault would see 104[VAC], due to theseries combination of the two legs. On the other hand, an intra-devicefault could see 208[VAC]. A leg to neutral fault would see 120[VAC]across the present invention. Application specifics, electrical and firecodes, will determine whether worst case design parameters should beapplied. In the resonant case, the voltage requirement for theintra-device fault would be approximately 312[VAC_(RMS)], whichcorresponds to 442 Volts peak-to-zero. This would require a minimum DCbias voltage of 221[VDC] and a capacitor rated voltage in excess of442[VDC], neglecting capacitor component error and AC system voltagevariation.

Note that circuit fault protection and surge protection are importantdesign parameters for all applications. Basic considerations alsoinclude network available symmetric and asymmetric fault currents.Suitable equipment should be provided to allow clearing of downstreamfaults without unnecessary damage to the instant invention. Fuses,circuit breakers, switching, ground fault circuit interrupters, currentlimiting devices and solid-state devices are considered for this duty.Application specifics will determine an appropriate combination ofprotection elements. MOVs and other surge arrestors can be placed inshunt to neutral and ground to reduce voltage surges and spikes.Similarly, they can be placed in shunt with the present invention. Thiswill similarly reduce damage to device components in high voltageconditions.

Two-port circuit parameter analysis techniques apply, and most two portinterconnections are allowed. These tools apply to the instantinvention; as with any other AC capacitor implementation, when the ACterminals of the instant invention, are treated as a black box. It isnoted that, a set of engineering approximation disclaimers, aretypically enunciated, in the use of such techniques. These include,within engineering approximations, first order approximation, simplemodel and the like.

Inrush, starting and fault currents exhibit extremely low, lagging powerfactors, on the order of fifty percent, (0.5, Lagging). In some casesthe magnitude of these currents can be reduced by the presence of seriescapacitance. The maximum current is an important design consideration incircuit analysis and conductor selection. The duration of motorstarting, rotor lock, inrush currents, full load currents and faultcurrents should similarly be considered in network analysis and seriescapacitor sizing. The instant invention is suitable for fault analysisusing the sequence method and other standard fault calculations.

The instant invention is suitable for use in shunt with AC loads and/orsources. The AC circuit will exhibit resonant current phenomenon similarto that detailed with respect to voltage in series applications. Shuntcapacitors are typically current limited or time limited by cyclingcontrols in AC network applications. The high capacitance provided bythe instant invention will provide an improvement to available worldutilities in shunt configurations as well as in series applications.PECS device design considerations in shunt configurations include ACcurrents of up to 150% of the AC source provided current. The low ACimpedance of the instant invention may produce a virtual short ifcurrent limiting methods are ignored. A current limiting load such as aresistor may be placed in series with the anti-series PECS deviceconfiguration in AC shunt applications. If the resistor is doing usefulwork, the energy is not lost.

Resonance is well defined and understood by those skilled in the trade.The two most basic manifestations of this phenomenon are series andparallel resonance. Circuit resonance is sometimes the object of adesign. On other occasions, resonance is unplanned and destructive.Circuits with resonance phenomenon will display currents and/or voltagesfar in excess of those seen in non-resonant operation. It is typical toincrease circuit current capacity and/or voltage ratings by more thanfifty percent when resonant conditions are expected. Design of resonantsystems should include additional heat dissipation measures due to thehigh voltage and/or current conditions. The loss angle (delta), andmeasured heat generation become important design criteria in such cases.In some applications a circuit may be tuned to resonate only during lowsystem voltage conditions. This allows the voltage rise associated withseries resonance to offset the low voltage system condition. Ananalogous design could be used for current maintenance with a shunt, orhybrid resonant design.

Transient network voltage surges and spikes should also be consideredwith the present invention. Such rises in voltage due to lightning,switching operations and similar events have great bearing upon allequipment. Inductors, MOVs, avalanche diodes and other surge arrestorsmay have some utility in protecting circuits of the present inventionand other connected equipment from damage. The instant inventionprovides some transient protection to connected loads, by virtue of thecapacitive opposition to instantaneous voltage change. If thetransmission time constant is longer than that of the MOV to ground, theload may be spared. Also standard design constraints regarding currentlimitation and circuit protection should be employed. For example, takethe case of a sinusoidal waveform. The peak to zero voltage magnitude isgreater than the RMS value by a factor of root two. Thus for a 120[VAC]source, the actual peak to zero voltage value is 169.71 Volts. In thethree phase case of (120:208)[VAC], and the latter figure is the line toline RMS voltage, and differs from the line to neutral voltage by afactor of root 3. The equivalent line to line peak to zero voltage isthus, 293.94[VAC].

Most useful AC electrical loads have lagging power factors. The instantinvention can add a stable leading power factor device to the publicutility. When connected in series with resistive and/or lagging powerfactor loads, an improved, unity or leading power factor can be realizedas seen by the AC source. The capacitive circuitry, and/or inductiveelements may be switched in and out of the network as needed. Banks ofanti-series capacitors may be separately controlled and when switched inor out of the circuit, the overall circuit parameters are altered. Thenet result is increased efficiency, control and stability of powertransfer. In addition, signal transfer fidelity and energy storage maybe increased as needed. These are valuable additions to the publicutilities.

Inrush currents create significant problems in electric grid voltageregulation. Series capacitors have the capability of improving the powerfactor of the inrush currents. Improved instantaneous power factorreduces the instantaneous current magnitude requirements, on theconnected source or electric utility. Polarized capacitor AC impedanceis observed to increase, with conducted current, another currentlimiting feature of the instant invention. Reduced instantaneous currentrequirements, reduces instantaneous power transmission and distributionloss. Reduced transmission and distribution losses, reduces demand onthe source or connected utility. Thus we see that reduced inrush andstarting requirements increase the network instantaneous reserve powercapacity and stability. Other current limiting methods are disclosedherein and/or alluded to herein and claimed.

Steady state voltage regulation is a similar application of the presentinvention. A series bank of capacitors can be subdivided. As AC loadincreases, additional capacitors can be brought on line via staticswitch, electromechanical contactor or other mechanisms. By this method,the series resistance of the capacitor bank is reduced. Similarly, in aresonant application, the addition or subtraction of capacitance canhave a profound influence on network AC voltage. Thus, AC voltageregulation can be one of the uses of the present invention. In somecases, two AC systems have different DC bias conditions. If they have acommon magnitude and are phase locked, the present invention can be usedto couple them together. The present invention can provide an alternateisolating AC coupling method. It is expected that many applications willensue from this utility.

The instant device can be used in a continuous duty, single phase, splitphase motor and/or capacitive AC induction motor. Thus, both windingscan be used continuously, when wound for such duty. This vectoralcurrent manipulation will define single-phase motor rotation direction.It will further serve to eliminate the 120-Hertz vibration (hum), whichis present in single-phase motors. This implementation will allow theelimination of the disconnection circuitry. Alternately, the split phasemotor design may be reversed, removing the lagging wind from serviceafter startup. Clever application of precisely regulated vectoralcurrents may be used to economically improve synthesis of three-phaseelectricity from a single-phase source.

Practical realizations of the present invention may require bleedresistors or the like in parallel with the polarized capacitors. Thiswill provide increased personnel safety during maintenance operations.Bleed resistors can be full time devices, or alternately may be switchedinto the circuit, when the unit power supply has been disconnected ordisassembled. Many electrical specifications explicitly call for bleedresistors. While some responsiveness, efficiency and stability are lostwith the addition of bleed resistors, they do not pose a significantperformance problem with the instant invention. Such resistors serve theadditional purpose of reducing AC and DC voltage variation impressed onthe capacitors due to capacitor component tolerance and/or componenterror. It is noted that capacitance, impedance, leakage currents and thelike vary with temperature, age and other service conditions. Suchfactors become of importance where multiple series and/or antiseriesassemblies are employed.

Where series resonant conditions are encountered, it will be desirableto increase capacitor voltage ratings and DC bias voltage magnitudes.Transient resonance conditions in AC networks may require a controlled(regulated) DC bias power supply, in applications otherwise served byuncontrolled supplies. An optional, non-controlled floating DC biasingscheme, which nonetheless provides an appropriate potential for variousoperation modes is discussed, and claimed herein. The series loadresistance and internal capacitor resistances will typically damp someresonance phenomena. Capacitor specifications in AC network conditionsdo not typically require such high voltage ratings. This may become amore prevalent design requirement with the advent of widespread use, ofpolarized capacitors, in AC networks.

Moreover, induction generators have significant trouble poweringinduction motors. There is a substantial deficit of magnetizing VARs.The present invention provides a plethora of capacitive reactance, andthus substantially improves such applications. In that inductiongenerators are substantially less expensive than synchronous generators,great economic benefit is expected to ensue.

Both resonant and non-resonant applications may be considered (for anyfrequency below the self-resonance frequency of the polarized chargestorage device) and can be calculated and/or measured. Similarly, otherarbitrary waveform applications may be selected for calculation and/ormeasurement. In the following example, an application using computergrade, large aluminum can, electrolytic capacitors, in a non-resonant,sinusoidal, sixty 60[Hz] case is considered. In this example, simplefirst order calculations are to be performed.

Consider a simple distribution load application where the maximum steadystate current is 10[A], and the maximum transient condition is 90[A].The duration of the transient condition is assumed to be thermallysignificant. The system voltage is 120[VACRMS], plus or minus 10%. Theambient operating temperature selected is 45[° C.]. A forwardly biased,anti-series polarized capacitor pair of the present invention will beplaced in series with a single source and load. (The anti-series pairwill be placed in the hot lead.) Capacitance is assumed to be +/−20% ofnominal. A design factor of 10% will be applied. The simple, first ordercalculations shall assume moving air conditions with no heat sink orother thermal capacitor design or application thermal enhancement.Temperature and frequency corrections and capacitor manufacturingtolerances are ignored in this example. Similarly, voltage margins forreduced signal distortion and life extension are neglected.

Let:

Vrms=Root Mean Square of the AC Voltage

Vpp=Magnitude of the AC Voltage wave, peak to peak

Vpo=Magnitude of the AC Voltage wave, peak to zero

Vhalf=AC voltage across a single capacitor of a series anti-series pair

Vsurge=Capacitor rated maximum DC surge voltage

WVDC=Rated DC voltage of the Capacitor

Vbias=Capacitor DC bias voltage

Dfac=10% Design Factor

Cfac=20% Capacitance Variation

Note that:

Vpp=2Vpo=2Vhalf=2Vrms(root two)

It is observed that the instantaneous superposition of Vbias plus Vhalfmust remain below the WVDC. It is also noted that the magnitude of Vbiasmust equal or exceed Vhalf to maintain a continuous positive DC biasvoltage condition across the polarized capacitor. It is further observedthat the AC voltage steady state magnitude is maximized when the DC biasvoltage is ½ the magnitude of WVDC. The AC surge magnitude is maximizedwhen the DC bias voltage is ½ the maximum DC Surge voltage range of thecapacitor. We thus observe that (Vbias+Vhalf), must be equal to orgreater than (GE), the magnitude of the system AC voltage. AC voltagedivision is affected by the variation in the actual capacitance of thecapacitors. Therefore, with an allowance of 20% for capacitancevariation and for the 10% system voltage magnitude variation, we have:

(Vpp)×Dfac×Cfac=(169.71×2)×1.10×1.20=448.03 Volts.

On a per capacitor basis, this becomes

(Vpo)×Dfac×Cfac=(169.71)×1.10×1.20=224.02 Volts.

The AC voltage will be divided across the two anti-series wings of theinstant invention. Thus we can make a first order device selection fromthis information.

A recent Cornell Dubilier Catalog lists the model numberDCMC123T450FG2D. This capacitor is listed with a nominal capacitancevalue of 12,000 microFarad, ESR of 13.3 milliOhms, and a maximum ratedAC ripple current of 24.0 Amps. The WVDC and Vsurge are 450 VDC and 500VDC respectively. For this case Vbias shall be selected to be WVDC/2 or225 Volts DC. This will correspond to a nominal superposition voltageof:

Vhalf+WVDC/2=449.02 Volts.

Selecting eight total capacitors (4 per side) will provide a currentrating of 96 Amps.

The total nominal capacitance of the device is 12,000×4/2=24,000microFarad. The nominal ESR is 6.65 milliOhms, the capacitor impedanceis on the order of 12 milliOhms, and the magnitude of the load impedanceis 1.33 Ohms and 12.0 Ohms for the transient and steady state conditionsrespectively. The steady state AC voltage drop across the capacitorassembly is on the order of 0.12 Volts, and the drop across eachcapacitive wing is 1.1 Volts in the more severe transient condition. Inthis example, we see that except for the resonant and fault conditions,the capacitor voltage rating is much higher than necessary. Theadvantages to considering lower voltage capacitor ratings are size,weight, capacitance and cost. The disadvantages are device destructionin fault, or resonant conditions. As always, application economics, andsafety concerns will normally decide the issue. This device could beconstructed using fast fuses, surge arrestors, bleed resistors, meteringand polishing capacitors for a more robust design.

Technicians should exercise a high degree of care in handling circuitsconstructed to the design standards herein. The most widespreadelectrical industrial standard of, ‘Lock Out, Tag Out’, is notsufficient for safety. The large electrical capacitors, which may beutilized in the present invention, may remain electrically charged formany days, unless suitable bleed resistors, or the like, are provided.The high voltage conditions present; clearly constitute alife-threatening hazard. An extreme degree of caution is thereforerecommended to anyone handling the charged devices of the presentinvention. Those unskilled in the art should avoid contact with thecircuits and circuit elements. For example, a d' Arsonval meter placedin shunt, with a polarized capacitor, may short the DC bias voltage aswell as the AC source. This will disrupt the process entirely and mayburn up the ammeter. It may also cause capacitor reverse biasing, withthe attendant shorting and subsequent rupture. Those unskilled in thedesign of this circuitry should exercise extreme caution in addingcircuit elements. A coil or small resistor placed in shunt with apolarized capacitor will duplicate the results of the meter mistakeabove. For this reason, the normal course should be to use the polarizedcapacitor assembly as a unit.

PECS device self-resonance phenomenon can be shunted to ground with anappropriate RFI filter, or damped if it occurs.

The frequency response of the PECS device circuits herein provides auseful addition to certain variable frequency devices. The reduction ofcircuit effective capacitance with increasing frequency partiallyoffsets the impedance drop with increasing frequency. For example, thepower transfer efficiency within a variable speed drive may be enhanced,while low frequency current limiting is provided. Thus, the drive mayoperate with improved power factor over an extended frequency range.

Full wave rectifiers may be constructed by coupling a single PECS deviceto each terminal of an AC power source as though in an anti-seriesconfiguration. The center node is then broken apart. A RectificationBridge and DC output section is then connected to the free ends of thePECS devices, where the DC junction node had been. The DC output is thenput to use in floating DC applications. A volt divided portion of the DCoutput is snubbed back to the PECS devices for biasing purposes. Thisdesign eliminates the need for an isolation transformer to power abattery charger or DC power supply. In addition the power factor of therectifier will be corrected relative to the lagging power factor of anisolation transformer powered device. This circuit may be constructed insingle phase or polyphasic applications. Other similar energy conversiondesigns are envisioned herein.

There exist applications exploiting the terminal characteristics of thediscreet components. A volt divider is present, and properly designedfilters can be used. High pass, low pass, band pass and blockingfilters, tied to the center node, should be attempted with extremecaution, and personnel shielding. It is considered that circuit designconsiderations including magnetic saturation, resonance, Bode plots,Nyquist plots, and the like are well known, to those who are familiar,with the art.

Along these lines, there are many circuit realizations suitable forestablishing and maintaining the proper DC capacitor bias condition. TheDC may be derived from any suitable scheme including both regulated andunregulated sources. Care is taken to avoid ground loops and DC biasingof the AC supply; typically through the use of electrical isolation viatransformer, and ungrounded secondaries (floating DC power supplies). Inaddition, batteries can be used in the system, to increase reliability.Battery supplies provide a redundant power supply for the period oftheir designed backup. A small, electrochemical battery, will providemany days of sufficient active DC bias supply, based on the slow decayof charge in polarized capacitors. The selection of a battery technologyis application specific. Factors including price, ambient temperature,seismic conditions, AC power reliability, ventilation, expectedlifetime, and the like, dictate battery selection. The battery maximumcharging voltage and final discharge voltage, or DC system design shouldkeep the polarized capacitor out of the AC signal clipping ranges.

The highest DC bias voltage levels are required in resonance, fault,motor starting, transformer inrush, switching operations, system voltagespikes and like conditions. Lower bias voltage may be employed in otheroperating conditions to prolong capacitor life. This voltage adjustmentcan be automatic with an appropriate feedback system. Additional circuitelements such as bleed resistors, loading resistors, harmonicfiltration, voltage surge arrestors, non-polarized polishing capacitors,over current protection, ground fault protection, switching mechanisms,diagnostics and the like, can be added, as required, for electricalsafety concerns and particular applications. Other implementations mayinclude contactors, DC pre-charging, soft start mechanisms and the like.Alterations and adaptations of this nature do not constitute asignificant deviation from the process presented herein.

There exist numerous methods of implementing the present invention. Thetwo broadest areas are the bias source and the AC/DC interface. Thebreadth of these subjects; is considered to be incorporated herein. Inmanufacturing and implementations of the instant invention, it isexpected that various schemes of economy will be adopted. For example,discrete diodes are shown on the drawings herein. Various diodecombinations exist in the marketplace today. Two such commoncombinations are the bridge rectifier and the common cathode dual diode.Devices such as this reduce the discrete component count and thus, themanufacturing cost. Multi-pole capacitors are another method of reducingassembly connection steps. The Wheatstone bridge is a similar resistivecombination. Indeed, the theme of micro-circuitry design economics hasbeen the progressive reduction in discrete components. Such labor savingutilities are explicitly incorporated herein. It is further assertedthat various capacitor cooling strategies and shock hazard protectionsystems will be employed in embodiments of the instant invention. Suchthermal regulation and electrical insulation methods and designs areexplicitly incorporated herein.

Further, in some applications explicit interfaces are most economicallyincluded, while other applications will make use of, existing externalcircuit topology. All device capacity levels, as measured in amperage,voltage and/or frequency response are included in the present invention.Similarly, all suitable polarized electrical charge storage devices areembraced herein. This invention may be embodied in other specific formswithout departing from the spirit or essential characteristics thereof.It is important to note that in each of the above embodiments, thecomponents may be scaled up or down, in size. Representative circuitdesigns and method of fabrication thereof are outlined. The mosteconomical realization will vary, according to application variables,including but not limited to: system voltage, steady state currentrequirements, transient current requirements, resonance probability,selected capacitor model characteristics, bias power supply selection,environment, redundancy requirements, external fault considerations,internal fault considerations and the like.

Additional objects, advantages and novel features of the invention areset forth herein, or will become apparent to those skilled in the art,upon examination of this disclosure, or may be learned by practice ofthe invention. The objects and advantages of the invention may berealized and attained, by means of the instrumentalities, andcombinations particularly pointed out, implied herein and/or familiar tothose in the trade. The embodiments, of the present invention, describedherein; are intended, to be taken, in an illustrative and not a limitingsense. Various changes, modifications, alterations and additions may bemade to these embodiments: by persons skilled in the art, withoutdeparting from the scope of the present invention as defined herein. Allchanges, which come within the meaning and range of equivalency, of theclaims, and other disclosures herein, are therefore, intended to beembraced therein. Many continuous and/or transient, uses and/orapplications of capacitors in AC networks are known to those practicedin the art, including but not limited to: resonance, commutation,snubbing, ferro-resonance, surge protection, compensation, energystorage, fault control, voltage regulation, current limitation, controlsignal transmission and the like. It is further intended that the claimsand disclosures be interpreted to cover all such applications,alterations and modifications, as fall within the true spirit, scope andmeaning of the invention.

APPENDIX A: GLOSSARY OF TERMS

The term “anti-series” refers to two or more PECS devices coupledtogether at their anodes and/or their cathodes. That is, anti-seriesPECS devices have a DC junction node at their anodes, cathodes, or boththeir cathodes and anodes. This is to be considered in its broad sense,and shall not, for example, exclude manifold configurations of largernumbers of components such as with multiple PECS device anodes (orcathodes) connected substantially together at a DC junction node incurrent divider designs. For example, five PECS devices, in a starconfiguration with their anodes connected together, would each be inanti-series configuration with one another. It is noted that PECSdevices in the various legs of a polyphasic AC system may also be in ananti-series configuration with one another. Similarly, in identifying aPECS device in an anti-series configuration, any given device mayactually include multiple shunt-configured devices for, e.g., increasingampacity. Additionally, several series PECS devices may be joinedtogether in an anti-series fashion in order to increase the effective ACvoltage rating. Likewise, several anti-series PECS device pairs maythemselves be joined in a series fashion to increase the effectivevoltage rating. Finally, it is noted that AC system components (such asAC sources or loads) may actually be connected between anti-seriesdevices at a DC junction node.

The term “AC” and “AC source” are used in their broad sense. The term ACand AC source shall include but are not limited to fixed frequency,variable frequency, fixed amplitude, variable amplitude, frequencymodulated, amplitude modulated, and/or pulse width modulated AC. Othersignal and/or communication techniques including sideband andsuperposition as well as other linear, nonlinear, analog or digitalsignals and the like are expressly included. AC sources may includeharmonic components. AC and AC source are considered to refer to timevarying signals. These signals may contain data and/or power. Hybrid ACsources varying in multiple methods and/or modes are similarly included.References to a single AC source shall not be construed to eliminateplural AC sources.

The term “AC blocking device” shall include any device, method, designor technique that provides a relatively large AC impedance, as comparedwith associated anti-series PECS devices, and at the same time may beconfigured to provide a DC current path for biasing such PECS devices.For example, an AC blocking device could include but is not limited toresistors, inductors, rectifiers, electrical switches and the like.

The terms “continuous and steady state”, as used herein are not intendedto indicate any unsuitability for transient applications such asstarting and the like.

The terms “DC”, “DC electricity” and “DC current” may be any technology,design, condition, physical condition or device, creating, causing,contributing, supporting, or favoring a unidirectional or predominantlyunidirectional flux, displacement, transmission and/or flow of one ormore electrical charge carriers including but not limited to electrons,ions and holes. This shall not be construed to exclude thebi-directional travel of oppositely charged particles. DC shall referbroadly to a steady state voltage that does not substantially vary withtime.

The term “DC source”, “DC voltage source” or “DC power source” is usedin its broad sense. This term generally covers and includes any methodand device used or useful in the generation, production or ACrectification to produce DC electricity. DC power supplies expresslyinclude, but are not limited to DC generators, electrochemicalbatteries, photovoltaic devices, rectifiers, fuel cells, DC quantumdevices, certain tube devices and the like. They shall includeregulated, unregulated, filtered and non-filtered types. DC sourcesshall expressly include but are not limited to rectifiers powered bynon-electrically isolated sources, autotransformers, isolationtransformers, and ferroresonant transformers. DC-to-DC supplies,switching DC power supplies, pulse chargers and the like are similarlyincluded. The singular term shall not be construed to exclude multipleand/or redundant DC sources in shunt, series and/or anti-seriesconfigurations. Single phase and polyphasic DC sources and/or chargersare included. The ability to adjust the DC bias level in real time issimilarly included. The use of ‘diode dropper devices’ and preciselyregulated floating DC power supply voltages can provide operational anddesign benefits, especially where electrochemical batteries are includedfor power source redundancy, or are the anti-series PECs deviceemployed.

The term “DC bias source” is used in the broad sense. This termgenerally covers and includes any method, design and/or device used oruseful in the production and distribution of DC voltage and current toPECS devices while limiting, restricting and/or blocking the flow of ACcurrent. The term DC bias source may include, but is not limited to, atleast one DC voltage source substantially in series with at least one ACblocking device. In the instant invention, one or more DC bias sourcesare connected across PECS devices for the purpose of establishing andmaintaining a forward DC bias voltage across said PECS devices. The DCbias source will prevent the AC source from reverse biasing orexcessively forward biasing the connected PECS device. A single DCvoltage source can be configured to serve as a DC bias source fornumerous PECS devices by means of appropriately connected DC conducting,AC blocking devices. Similarly, multiple DC voltage sources and/or DCbias sources may be configured to provide redundant bias voltage sourcesto anti-series PECS devices in an AC application.

The term “DC junction node” corresponds to a node in a configuration oftwo or more anti-series PECS devices where like-polarity device nodesare coupled together. It should be noted that a DC junction node may (ormay not) incorporate one or more AC devices (such as an inductor) withnegligible DC voltage across the AC device. That is, there issubstantially no DC voltage difference within a DC junction node.Similarly DC bias circuitry, meters, indicators, alarms and the like maybe connected to DC junction nodes.

The term “electrical isolation” is used in its broad sense. This termgenerally includes but is not limited to isolation transformers,ferro-resonant transformers and separately produced, inverted and/orgenerated electrical power supplies in the case of AC. DC isolation maybe accomplished by the use of capacitors. The term electrical isolationshall include DC power supplies that are produced, rectified orgenerated separately. Electrical isolation is intended to convey theability to have no fixed ground reference, select a common neutral,ground, reference voltage or to alternately select distinct neutrals,grounds or reference voltage. The selection occurs at the time ofconnection or operable connection, and is not necessarily intrinsic tothe design, construction, materials or character of the power supplies.

The term “polarized electric charge storage” (“PECS”) device is used inthe broad sense. This term generally covers any suitable polarelectrical charge storage device, and/or apparatus which includes but isnot limited to electrolytic capacitors, electrochemical batteries,certain electrical tube devices, semiconductor capacitive devices,photo-voltaic devices, fuel cells quantum charge storage devices and thelike. For the purposes of this document, a polarized electric chargestorage device may be any technology or device supporting a staticseparation of charge, favored charge storage polarity and a capabilityto conduct, displace and/or transmit electrical current. In many partsof this document, polarized capacitors are used—both in description andthrough illustration—for demonstrating various aspects of the presentinvention. However, it should be recognized that any suitable PECSdevice may be used both in place of or in cooperation with therepresented polarized capacitors. That is, none of the other PECStechnologies, referred to, or described, are intended to be excluded.

The term “rectifier” is used in its broad sense herein. Any active orpassive device and/or apparatus favoring or configured to favor aunidirectional flow of electrical charge carriers shall be considered arectifier. The bi-directional flow of oppositely charged particles isexpressly included within the definition of a rectifier. Rectifierincludes but is not limited to one or more diodes, transistors, siliconcontrolled rectifiers, cut off SCRs, thyristors, IGBTs, FETs, splitrings, certain tube devices and the like. Rectifying circuitconfigurations include but are not limited to half-wave, full-wave,split-wave and polyphasic rectifiers. Rectification pulses can be phaseshifted to oppose, match or offset either AC current or voltagewaveforms in the single or polyphasic cases. This can be accomplished byisolation transformer dot convention, phase shift winding methods, I/Olag, or electronically to name a few common methods.

The term ‘sufficiently forwardly DC biasing’ refers to the methods,devices and/or apparatus outlined or implied herein to maintain a DCbias voltage across a PECS device to substantially prevent the devicefrom being detrimentally reverse biased by an AC signal. The DC biasvoltage can be fixed to any arbitrary degree in the steady state. Thiscontrasts with the oscillatory bias schemes of the prior art, whichcharacteristically vary between a forward and reverse DC bias voltage ona sub-cycle basis and/or cause AC signal distortion because of excessivesignal size relative to DC bias voltage magnitude. DC biasingconsiderations include operation within the applicable PECS deviceforward voltage limitations. Similarly included are bias conditionswherein the DC bias voltage magnitude of each PECS device substantiallyexceeds the magnitude of the impressed AC signal.

The terms ‘switch’ and/or ‘electrical switch’ refer to the methods,devices and/or apparatus by which an electrical current may be turned onor turned off. Switch shall include mechanical conductor contactdesigns, electromechanical devices, semiconductor devices, relays,liquid contact devices such as mercury switches, molecular switches,ionization devices, valves, quenchers, gates, quantum devices and thelike. In addition, differential devices such as rheostats,potentiometers that may serve as dimmers and/or flow regulators, as wellas on/off devices, and the like are included. Any state of matter and/orchange in state of matter, used to effect the control of electricalflow, flux, current or conduction, displacement and the like isconsidered to be included in the term switch. Similarly, the sensors,actuators, controls, relays, circuit boards, chips and the likeassociated with various technology switches are included. Electricalswitch and switch when used within this paper shall be construed in thebroad sense. The devices and methods outlined herein are illustrativeand not limiting.

The term “DC blocking device” shall include any device, method, design,apparatus and/or technique that provides a relatively large DCresistance and/or opposition to the flow of DC current. For example, anDC blocking device could include but is not limited to polarizedcapacitors, non-polarized capacitors, electrochemical batteries, otherPECS devices, resistors, rectifiers and the like. Similarly, anisolation transformer serves as a DC blocking device, in that DC is notmagnetically coupled. It is noted that rectifier bridges provide ahigher order of DC blocking than is provided by a single rectifier or ahalf wave bridge.

The term “temperature regulation” shall mean the control of PECS devicetemperature by natural or artificially powered means to alter thesurface and/or core temperature of the device. Typical methods oftemperature regulation include water baths, oil baths, refrigerants,circulating systems with heat sinks, and the use of heating elements andheat exchangers. Heat pumps, solid state cooling and other such methodsare suitable for the maintenance and/or alteration of devicetemperature.

The term “transient” as used herein is not intended to indicateunsuitability for steady state or continuous applications.

What is claimed is:
 1. A polarized electric charge storage (“PECS”)apparatus for operation in an AC network having an AC source and atleast one load coupled to the AC source for receiving the AC signal, thePECS apparatus comprising: at least first and second PECS devices in ananti-series configuration with one another, the anti-series PECS devicesadapted to be operably connected to the AC network and subjected to theAC signal, and at least one DC source coupled to the first and secondPECS devices for sufficiently forwardly DC biasing the devices tosubstantially prevent them from being detrimentally reverse biased bythe AC signal.
 2. The apparatus of claim 1, wherein the at least one DCsource is operably coupled to the first and second devices so that theAC signal is not substantially conducted through the at least one DCsource.
 3. The apparatus of claim 1, wherein the anti-series PECS deviceconfiguration is adapted to be connected substantially in shunt with theAC load.
 4. The apparatus of claim 1, wherein the anti-series PECSdevice configuration is adapted to be connected substantially in seriesbetween the AC source and the AC load.
 5. The apparatus of claim 1,wherein at least one output terminal of the at least one DC source isadapted to be electrically isolated from the at least one AC source. 6.The apparatus of claim 1, wherein the at least one DC source isungrounded.
 7. The apparatus of claim 1, wherein at least one outputterminal of the at least one DC source is adapted to be operablyconnected to an AC system ground.
 8. The apparatus of claim 1, whereinthe first and second PECS devices are symmetrically DC biased withrespect to one another.
 9. The apparatus of claim 1, wherein the firstand second PECS devices are connected to each other at a DC junctionnode, wherein the apparatus further includes at least one AC blockingdevice connected between the DC junction node and a DC reference node.10. The apparatus of claim 9, wherein the at least one AC blockingdevice comprises a resistor that has a sufficiently high impedancecompared to the first and second PECS devices for blocking the AC signalso that it substantially passes through the PECS devices.
 11. Theapparatus of claim 9, wherein the DC junction node incorporates at leastone AC device between the first and second PECS devices.
 12. Theapparatus of claim 9, further comprising an AC blocking device betweenthe DC junction node and another node from the first and second PECSdevices.
 13. The apparatus of claim 9, wherein the at least one DCsource includes first and second DC sources for separately biasing thefirst and second PECS devices.
 14. The apparatus of claim 13, whereinthe first DC source is substantially in shunt across the first PECSdevice.
 15. The apparatus of claim 14 further comprising an AC blockingdevice operably connected between the first DC source and the first PECSdevice.
 16. The apparatus of claim 15, wherein the second DC source issubstantially in parallel across the second PECS device.
 17. Theapparatus of claim 16, wherein the second DC source is connectedsubstantially in parallel across at least the second PECS device throughat least one AC blocking device.
 18. The apparatus of claim 17, whereinat least one terminal of the first DC source and at least one outputterminal of the second DC source are ungrounded.
 19. The apparatus ofclaim 17, wherein at least one terminal of the first DC source and atleast one output terminal of the second DC source are electricallyisolated with respect to the AC source.
 20. The apparatus of claim 9,wherein the at least one DC source includes a first DC source havingfirst and second output terminals for providing a DC potential, thefirst output terminal being coupled to the DC junction node, and thesecond output terminal being coupled to another node from the first andsecond devices.
 21. The apparatus of claim 20, further comprising atleast one AC blocking device in series between the DC junction node andthe first output terminal.
 22. The apparatus of claim 20, furthercomprising at least one AC blocking device in series between the anothernode of the first and second devices and the second output terminal. 23.The apparatus of claim 1, wherein the AC network is a polyphasic ACnetwork with an AC leg for each phase of the network, wherein the firstPECS device is adapted to be part of a first AC leg, and the second PECSdevice is adapted to be part of a second AC leg.
 24. The apparatus ofclaim 1, wherein the AC network is a polyphasic AC network with an ACleg for each phase of the network, wherein the first and second PECSdevices are adapted to be part of a first AC leg.
 25. The apparatus ofclaim 1, wherein the PECS configuration is adapted to be operablymounted in the AC network for steady-state operation.
 26. The apparatusof claim 1, wherein the first and second PECS devices are mounted in acommon enclosure.
 27. The apparatus of claim 26, wherein the first andsecond PECS devices are suspended in a dielectric fluid and mounted tothe enclosure with an insulated fastener, wherein the enclosure definesan electrically touch-safe container.
 28. The apparatus of claim 1,wherein the load is a split phase AC induction motor, and the PECSdevices are adapted to be connected in series between the AC source anda wind of said split phase motor and remain engaged for continuousoperation of the motor.
 29. The apparatus of claim 1, wherein said PECSdevices are part of an LC filter circuit having an inductor, the LCfilter circuit being tuned for a power fundamental frequency andadditionally having a switch for shunting the PECS devices upondetection of a downstream fault.
 30. The apparatus of claim 1, the ACsource being a first AC source, wherein a second AC source having adifferent AC voltage than the first AC source is operably connected tothe first PECS device via a current limited rectifier.
 31. A PECSapparatus for use in an AC application, comprising: a first PECS device;at least a second PECS device being connected in anti-series relation tothe first PECS device; and at least one DC bias source operablyconnected to said first and second PECS devices for sufficientlymaintaining said first and second devices forwardly biased while beingused in the AC application.
 32. The apparatus of claim 31, wherein theDC voltages for biasing the first and second devices substantiallycancel each other out with respect to the AC application.
 33. Theapparatus of claim 31, further comprising an AC electrical devicelocated between the anti-series PECS devices, wherein the AC device isoperated at a different DC voltage level than the connected ACapplication.
 34. The apparatus of claim 33, wherein the AC deviceincludes a DC power supply.
 35. The apparatus of claim 34, wherein aportion of the DC power supply is operably connected between theanti-series PECS devices for forwardly DC biasing said first and seconddevices.
 36. The apparatus of claim 31, wherein the anti-series PECSdevices are used to couple an AC neutral node within the AC applicationto a ground node.
 37. The apparatus of claim 31, the first and secondPECS devices each having a positive and a negative node, wherein atleast the positive or negative nodes from the first and second devicesare substantially connected together from a DC standpoint.
 38. Theapparatus of claim 37, wherein the positive nodes from the first andsecond devices are substantially connected together and the negativenodes from the first and second devices are substantially connectedtogether from a DC standpoint.
 39. The apparatus of claim 31, furthercomprising one or more PECS devices substantially connected in shuntacross the second PECS device, whereby the one or more PECS devices arein anti-series configuration with the first PECS device.
 40. Theapparatus of claim 39, wherein the one or more PECS devices are also inanti-series configuration with the second PECS device, whereby thefirst, second, and one or more PECS devices are in anti-seriesconfiguration with each other.
 41. The apparatus of claim 31, furthercomprising one or more sets of operably forwardly biased anti-seriesPECS devices connected to each other and to the first and secondanti-series device configuration at a DC junction node to form an ACcurrent divider manifold.
 42. The apparatus of claim 31, furthercomprising a non-polar capacitor connected substantially in parallelacross at least the first PECS device.
 43. The apparatus of claim 31,wherein the anti-series PECS devices are used for enhancing asteady-state AC application.
 44. The apparatus of claim 31, wherein theat least one DC source is operably connected to the first and secondPECS devices so that an AC signal from the AC application is notsubstantially conducted through the at least one DC source.
 45. Theapparatus of claim 31, wherein the anti-series first and second devicesare suspended in a dielectric fluid and mounted within an enclosure withan insulated fastener, wherein the enclosure defines an electricallytouch-safe container and provides electrical contacts for connection.46. An AC network, comprising: an AC source; an AC load operably coupledto said AC source; first and second PECS devices in anti-seriesconfiguration with one another operably coupled to said AC source andload; and at least one DC source for forwardly biasing said first andsecond devices for preventing them from being detrimentally reversebiased by said AC source.
 47. A method for using PECS devices in an ACnetwork having an AC source and an operably coupled AC load, comprising:implementing at least first and second PECS devices in an anti-seriesconfiguration within an AC network for enhancing operation of the ACnetwork, wherein an AC signal is applied to the anti-series devices; andsufficiently biasing each of the PECS devices with at least one DCvoltage source so that the devices substantially remain forwardly biasedduring operation of the AC network.
 48. The method of claim 47, whereinthe DC voltages across the at least first and second devicessubstantially cancel each other out with respect to the AC network. 49.The method of claim 47, wherein the act of implementing the anti-seriesPECS devices includes implementing first and second polarizedcapacitors.
 50. The method of claim 49, wherein the first and secondpolarized capacitors are coupled to each other at a DC junction node,the method further comprising providing an AC blocking device betweenthe DC junction node and a DC reference of the at least one DC source.51. The method of claim 50, wherein the act of implementing theanti-series devices within an AC network includes using the anti-seriespolarized capacitors in series between the AC source and the AC load forimproving the power factor with respect to the AC source.
 52. The methodof claim 47, further comprising adjusting AC network impedance as seenby the AC source by adjustably engaging the anti-series devices withinthe network.
 53. The method of claim 47, wherein the anti-series devicesare adjustably engaged with an electrical switch.
 54. The method ofclaim 47, wherein AC network parameters are altered by controllablyvarying the temperature of the PECS devices.
 55. The method of claim 54,wherein the act of controllably varying the temperature of the PECSdevices is performed with a heat exchange apparatus.
 56. The method ofclaim 47, further comprising providing a resistive device substantiallyin shunt across each of the first and second PECS devices for forwardlybiasing and balancing said devices in a voltage divider application. 57.The method of claim 47, further comprising providing at least one bleedresistor operably connected to the first and second PECS devices fordischarging the bias voltage across the PECS devices for safe shutdownand maintenance purposes.
 58. The method of claim 47, wherein themagnitude of the AC voltage impressed across each PECS device is lessthan the magnitude of the DC bias voltage across each PECS device. 59.The method of claim 47, wherein the steady state superposition of DCbias voltage and AC voltage impressed across each PECS device remainswithin the rated voltage of each PECS device.
 60. The method of claim47, wherein at least one electrically isolated DC bias source isconnected substantially in shunt across the first PECS device for use ina steady state AC application.
 61. The method of claim 47, wherein atleast one electrically isolated DC bias source is connectedsubstantially in shunt across the first PECS device for use in atransient AC application.
 62. The method of claim 60, wherein arectifier bridge is used to provide electrical isolation of rectified DCfor continuous charging of the first PECS device.
 63. The method ofclaim 62, wherein at least one DC pole of the DC bias source iselectrically isolated from at least one AC power source for continuousforward biasing of the first PECS device.